diff --git a/litellm/proxy/auth/ip_address_utils.py b/litellm/proxy/auth/ip_address_utils.py
index 558ea54495f..c2614b85016 100644
--- a/litellm/proxy/auth/ip_address_utils.py
+++ b/litellm/proxy/auth/ip_address_utils.py
@@ -6,8 +6,11 @@ External callers (public IPs) only see servers with available_on_public_internet
 """
 
 import ipaddress
+import os
+from collections.abc import Mapping
 from dataclasses import dataclass
 from typing import Any, Final
+from urllib.parse import urlparse
 
 from fastapi import Request
 from pydantic import TypeAdapter, ValidationError
@@ -137,7 +140,7 @@ class IPAddressUtils:
     @staticmethod
     def is_request_from_trusted_proxy(
         request: Request,
-        general_settings: dict[str, Any] | None = None,
+        general_settings: Mapping[str, Any] | None = None,
     ) -> bool:
         """
         Return True if X-Forwarded-* headers on this request should be trusted.
@@ -190,6 +193,36 @@ class IPAddressUtils:
         trusted_networks: Final = IPAddressUtils.parse_trusted_proxy_networks(trusted_ranges)
         return IPAddressUtils.is_trusted_proxy(direct_ip, trusted_networks)
 
+    @staticmethod
+    def is_request_https(
+        request: Request,
+        general_settings: Mapping[str, Any] | None = None,
+    ) -> bool:
+        """
+        Whether this request's PUBLIC-facing origin is HTTPS, for deciding
+        whether a cookie set on the response should be marked ``Secure``.
+
+        litellm only sees a plain-HTTP hop whenever TLS terminates at a
+        reverse proxy, so ``request.url.scheme`` alone cannot answer this in
+        that deployment shape. Resolved from the first trusted signal:
+          1. ``PROXY_BASE_URL`` (operator-declared public origin).
+          2. ``X-Forwarded-Proto``, only when the request's direct peer is a
+             configured trusted proxy -- see ``is_request_from_trusted_proxy``.
+             An untrusted caller cannot spoof this header to strip Secure.
+          3. The request's own literal scheme (direct TLS termination, or no
+             reverse proxy in front of litellm).
+        """
+        configured_base_url: Final = os.environ.get("PROXY_BASE_URL", "").strip()
+        if configured_base_url:
+            return urlparse(configured_base_url).scheme == "https"
+
+        if IPAddressUtils.is_request_from_trusted_proxy(request, general_settings=general_settings):
+            forwarded_proto: Final = request.headers.get("X-Forwarded-Proto")
+            if forwarded_proto:
+                return forwarded_proto.split(",")[0].strip().lower() == "https"
+
+        return request.url.scheme == "https"
+
     @staticmethod
     def extract_client_ip_from_xff_hops(
         xff_header: str,
diff --git a/litellm/proxy/management_endpoints/sso/saml_sso.py b/litellm/proxy/management_endpoints/sso/saml_sso.py
index 3e67b211f62..466b100ea1f 100644
--- a/litellm/proxy/management_endpoints/sso/saml_sso.py
+++ b/litellm/proxy/management_endpoints/sso/saml_sso.py
@@ -36,6 +36,7 @@ from pydantic import ValidationError
 
 from litellm._logging import verbose_proxy_logger
 from litellm.caching.dual_cache import DualCache
+from litellm.proxy.auth.ip_address_utils import IPAddressUtils
 from litellm.proxy.management_endpoints.types import CustomOpenID, get_litellm_user_role
 from litellm.proxy.utils import get_custom_url
 
@@ -131,7 +132,7 @@ class SAMLAuthHandler:
 
     @staticmethod
     def _is_https(request: Request) -> bool:
-        return SAMLAuthHandler._base_url(request).startswith("https")
+        return IPAddressUtils.is_request_https(request)
 
     @staticmethod
     def _acs_url(request: Request) -> str:
diff --git a/litellm/proxy/management_endpoints/ui_sso.py b/litellm/proxy/management_endpoints/ui_sso.py
index 6b98d9f9a26..1feefa5725d 100644
--- a/litellm/proxy/management_endpoints/ui_sso.py
+++ b/litellm/proxy/management_endpoints/ui_sso.py
@@ -92,6 +92,7 @@ from litellm.proxy.auth.auth_utils import (
     has_user_setup_sso,
 )
 from litellm.proxy.auth.handle_jwt import JWTHandler
+from litellm.proxy.auth.ip_address_utils import IPAddressUtils
 from litellm.proxy.auth.user_api_key_auth import user_api_key_auth
 from litellm.proxy.common_utils.admin_ui_utils import (
     admin_ui_disabled,
@@ -1118,7 +1119,7 @@ async def google_login(
             request=request,
         )
         if sso_redirect is not None:
-            _persist_return_to_cookie(sso_redirect, return_to)
+            _persist_return_to_cookie(sso_redirect, return_to, request)
         return sso_redirect
 
     from fastapi.responses import HTMLResponse
@@ -1138,7 +1139,7 @@ async def google_login(
     # helper the SSO branch uses, so /login can resume the connect flow instead of dead-ending at the
     # dashboard. One implementation → the two sign-in branches cannot diverge (and the login form always
     # renders, since the helper never raises on a bad return_to).
-    _persist_return_to_cookie(form_response, return_to)
+    _persist_return_to_cookie(form_response, return_to, request)
     return form_response
 
 
@@ -2741,6 +2742,7 @@ async def _sso_return_to_redirect(
     jwt_token: str,
     redis_usage_cache,
     user_api_key_cache,
+    request: Request,
 ) -> RedirectResponse | None:
     """Resolve the post-SSO redirect for a ``return_to``, or None to fall through to the dashboard.
 
@@ -2759,7 +2761,7 @@ async def _sso_return_to_redirect(
 
     if _is_same_origin_return_path(return_to):
         redirect_response = RedirectResponse(url=return_to, status_code=303)
-        redirect_response.set_cookie(key="token", value=jwt_token)
+        set_session_token_cookie(redirect_response, request, jwt_token)
         redirect_response.delete_cookie("litellm_cp_return_to")
         return redirect_response
 
@@ -2782,7 +2784,25 @@ async def _sso_return_to_redirect(
     return None
 
 
-def _persist_return_to_cookie(response: Response, return_to: str | None) -> None:
+def set_session_token_cookie(response: Response, request: Request, jwt_token: str) -> None:
+    """Set the ``token`` session cookie shared by every sign-in path.
+
+    Not HttpOnly: the dashboard reads this cookie via ``document.cookie`` to
+    populate its own Authorization headers (see
+    ``ui/litellm-dashboard/src/utils/cookieUtils.ts``), so marking it
+    HttpOnly would break login. Secure is still required whenever the public
+    origin is HTTPS, resolved the same trust-aware way as every other
+    litellm cookie."""
+    response.set_cookie(
+        key="token",
+        value=jwt_token,
+        secure=IPAddressUtils.is_request_https(request),
+        httponly=False,
+        samesite="lax",
+    )
+
+
+def _persist_return_to_cookie(response: Response, return_to: str | None, request: Request) -> None:
     """Best-effort: persist a SAFE ``return_to`` on ``response`` as the one-shot ``litellm_cp_return_to``
     cookie so ANY sign-in path — SSO / Okta / generic OR the username/password form — can resume there
     afterwards. THIS is the single source of truth, called by every sign-in branch so they cannot
@@ -2803,6 +2823,7 @@ def _persist_return_to_cookie(response: Response, return_to: str | None) -> None
             max_age=600,
             httponly=True,
             samesite="lax",
+            secure=IPAddressUtils.is_request_https(request),
         )
 
 
@@ -3079,8 +3100,11 @@ class SSOAuthenticationHandler:
                     # incoming request is HTTP (local dev).  Without
                     # ``Secure`` the cookie is sent over plain HTTP,
                     # letting a network observer read and replay the
-                    # state value and bypass this protection.
-                    secure_flag: Final = request is None or request.url.scheme == "https"
+                    # state value and bypass this protection. Trust-aware:
+                    # honors PROXY_BASE_URL / a trusted reverse proxy's
+                    # X-Forwarded-Proto instead of only the literal scheme
+                    # litellm sees on the wire.
+                    secure_flag: Final = request is None or IPAddressUtils.is_request_https(request)
                     redirect_response.set_cookie(
                         key="litellm_oauth_state",
                         value=state_value,
@@ -3628,6 +3652,7 @@ class SSOAuthenticationHandler:
             jwt_token=jwt_token,
             redis_usage_cache=redis_usage_cache,
             user_api_key_cache=user_api_key_cache,
+            request=request,
         )
         if return_to_redirect is not None:
             return return_to_redirect
@@ -3636,7 +3661,7 @@ class SSOAuthenticationHandler:
             litellm_dashboard_ui += "?login=success"
         verbose_proxy_logger.info("Redirecting to %s", litellm_dashboard_ui)
         redirect_response: Final = RedirectResponse(url=litellm_dashboard_ui, status_code=303)
-        redirect_response.set_cookie(key="token", value=jwt_token)
+        set_session_token_cookie(redirect_response, request, jwt_token)
         return redirect_response
 
     @staticmethod
diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 1e0792cb8a5..27132c90e05 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -15329,7 +15329,10 @@ async def login(request: Request):
     # authorize round-trip), mirroring the SSO callback; otherwise land on the dashboard. Gated by
     # _is_same_origin_return_path (strictly relative path) so it can never be an open redirect, and the
     # one-shot cookie is cleared after use.
-    from litellm.proxy.management_endpoints.ui_sso import _sso_return_to_redirect
+    from litellm.proxy.management_endpoints.ui_sso import (
+        _sso_return_to_redirect,
+        set_session_token_cookie,
+    )
 
     # Resume through the SAME resumer the SSO callback uses, rather than a second, narrower arm.
     # _persist_return_to_cookie stores both shapes it accepts (a relative same-origin path AND a
@@ -15346,6 +15349,7 @@ async def login(request: Request):
                 jwt_token=jwt_token,
                 redis_usage_cache=redis_usage_cache,
                 user_api_key_cache=user_api_key_cache,
+                request=request,
             )
         except Exception:  # noqa: BLE001  # resuming must NEVER block a completed sign-in
             # The symmetric half of _persist_return_to_cookie's "never raises" contract. The resumer
@@ -15360,7 +15364,7 @@ async def login(request: Request):
 
     # Create redirect response with cookie
     redirect_response: Final = RedirectResponse(url=litellm_dashboard_ui, status_code=303)
-    redirect_response.set_cookie(key="token", value=jwt_token)
+    set_session_token_cookie(redirect_response, request, jwt_token)
     if cp_return_to:
         redirect_response.delete_cookie(key="litellm_cp_return_to")
     return redirect_response
@@ -15370,6 +15374,7 @@ async def login(request: Request):
 async def login_v2(request: Request):
     global premium_user, general_settings, master_key
     from litellm.proxy.auth.login_utils import authenticate_user, create_ui_token_object, encode_ui_session_jwt
+    from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
     from litellm.proxy.utils import get_custom_url
 
     try:
@@ -15404,7 +15409,7 @@ async def login_v2(request: Request):
             content={"redirect_url": litellm_dashboard_ui, "token": jwt_token},
             status_code=status.HTTP_200_OK,
         )
-        json_response.set_cookie(key="token", value=jwt_token)
+        set_session_token_cookie(json_response, request, jwt_token)
         return json_response
     except Exception as e:
         verbose_proxy_logger.exception("litellm.proxy.proxy_server.login_v2(): Exception occurred - %s", e)
@@ -15504,6 +15509,8 @@ async def login_v3(request: Request):
 
 @router.post("/v3/login/exchange", include_in_schema=False)  # exchange single-use opaque code for JWT
 async def login_v3_exchange(request: Request):
+    from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
     try:
         if not general_settings.get("control_plane_url"):
             raise ProxyException(
@@ -15550,7 +15557,7 @@ async def login_v3_exchange(request: Request):
             },
             status_code=status.HTTP_200_OK,
         )
-        json_response.set_cookie(key="token", value=cached_data["token"])
+        set_session_token_cookie(json_response, request, cached_data["token"])
         return json_response
     except ProxyException:
         raise
diff --git a/tests/test_litellm/proxy/auth/test_mcp_ip_filtering.py b/tests/test_litellm/proxy/auth/test_mcp_ip_filtering.py
index e0585ab04f1..4c219760762 100644
--- a/tests/test_litellm/proxy/auth/test_mcp_ip_filtering.py
+++ b/tests/test_litellm/proxy/auth/test_mcp_ip_filtering.py
@@ -591,3 +591,100 @@ class TestFilterServerIdsByIpWithInfo:
         )
         assert allowed == []
         assert blocked == 2
+
+
+def _make_scheme_request(
+    scheme: str, client_host: str = "203.0.113.5", headers: dict[str, str] | None = None
+) -> Request:
+    request = MagicMock(spec=Request)
+    request.client = MagicMock()
+    request.client.host = client_host
+    request.headers = headers or {}
+    request.url = MagicMock()
+    request.url.scheme = scheme
+    return request
+
+
+class TestIsRequestHttps:
+    """Regression tests for the cookie Secure trust-boundary resolution.
+
+    litellm only sees a plain-HTTP hop when TLS terminates at a reverse
+    proxy, so a cookie's Secure attribute must not be derived from the
+    literal request scheme alone. It must also not blindly trust a
+    client-spoofable X-Forwarded-Proto header with no trust boundary.
+    """
+
+    def test_direct_https_is_secure(self, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request("https")
+        assert IPAddressUtils.is_request_https(request, general_settings={}) is True
+
+    def test_direct_http_is_not_secure(self, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request("http")
+        assert IPAddressUtils.is_request_https(request, general_settings={}) is False
+
+    def test_spoofed_forwarded_proto_without_trusted_proxy_config_is_ignored(
+        self, monkeypatch
+    ):
+        # Regression: an internal HTTP hop with an attacker-supplied
+        # X-Forwarded-Proto: https must NOT flip Secure on, because no
+        # trust boundary (use_x_forwarded_for + mcp_trusted_proxy_ranges)
+        # is configured. Blindly trusting this header is itself a
+        # vulnerability.
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request(
+            "http", headers={"X-Forwarded-Proto": "https"}
+        )
+        assert IPAddressUtils.is_request_https(request, general_settings={}) is False
+
+    def test_forwarded_proto_honored_only_from_trusted_proxy(self, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request(
+            "http",
+            client_host="10.0.0.5",
+            headers={"X-Forwarded-Proto": "https"},
+        )
+        general_settings = {
+            "use_x_forwarded_for": True,
+            "mcp_trusted_proxy_ranges": ["10.0.0.0/8"],
+        }
+        assert IPAddressUtils.is_request_https(request, general_settings=general_settings) is True
+
+    def test_forwarded_proto_http_from_trusted_proxy_is_not_secure(self, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request(
+            "https",
+            client_host="10.0.0.5",
+            headers={"X-Forwarded-Proto": "http"},
+        )
+        general_settings = {
+            "use_x_forwarded_for": True,
+            "mcp_trusted_proxy_ranges": ["10.0.0.0/8"],
+        }
+        assert IPAddressUtils.is_request_https(request, general_settings=general_settings) is False
+
+    def test_untrusted_direct_peer_falls_back_to_literal_scheme(self, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        request = _make_scheme_request(
+            "http",
+            client_host="203.0.113.5",
+            headers={"X-Forwarded-Proto": "https"},
+        )
+        general_settings = {
+            "use_x_forwarded_for": True,
+            "mcp_trusted_proxy_ranges": ["10.0.0.0/8"],
+        }
+        assert IPAddressUtils.is_request_https(request, general_settings=general_settings) is False
+
+    def test_proxy_base_url_https_overrides_literal_http_scheme(self, monkeypatch):
+        monkeypatch.setenv("PROXY_BASE_URL", "https://litellm.example.com")
+        request = _make_scheme_request("http")
+        assert IPAddressUtils.is_request_https(request, general_settings={}) is True
+
+    def test_proxy_base_url_http_overrides_literal_https_scheme(self, monkeypatch):
+        # An explicit operator-configured plain-http public origin wins over
+        # the literal connection scheme, same as the https direction above.
+        monkeypatch.setenv("PROXY_BASE_URL", "http://litellm.internal")
+        request = _make_scheme_request("https")
+        assert IPAddressUtils.is_request_https(request, general_settings={}) is False
diff --git a/tests/test_litellm/proxy/management_endpoints/test_saml_sso.py b/tests/test_litellm/proxy/management_endpoints/test_saml_sso.py
index 57decc7d458..36d6414ba9f 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_saml_sso.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_saml_sso.py
@@ -642,3 +642,77 @@ async def test_read_acs_post_data_rejects_oversized_stream_without_content_lengt
     with pytest.raises(HTTPException) as exc:
         await SAMLAuthHandler.read_acs_post_data(cast(Request, request))
     assert exc.value.status_code == 413
+
+
+def _fake_request_with_scheme(scheme, headers=None, client_host="203.0.113.5"):
+    """A fuller fake Request than ``_fake_request``: adds ``url``, ``headers`` and
+    ``client``, which ``IPAddressUtils.is_request_https`` reads directly instead of
+    going through ``PROXY_BASE_URL``."""
+    return type(
+        "Req",
+        (),
+        {
+            "base_url": URL(f"{scheme}://proxy.example.com/"),
+            "url": URL(f"{scheme}://proxy.example.com/sso/saml/login"),
+            "query_params": {},
+            "cookies": {},
+            "headers": headers or {},
+            "client": type("Client", (), {"host": client_host})(),
+        },
+    )()
+
+
+class TestSAMLAuthnCookieSecureFlag:
+    """Regression tests for the litellm_saml_authn cookie's Secure attribute.
+    litellm only sees a plain-HTTP hop whenever TLS terminates at a reverse
+    proxy, so Secure must not be derived from the literal request scheme alone."""
+
+    @pytest.mark.asyncio
+    async def test_secure_over_direct_https(self, saml_env, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        cache = DualCache()
+        request = _fake_request_with_scheme("https")
+        redirect = await SAMLAuthHandler.build_login_redirect(request, cache)
+        cookie = redirect.headers["set-cookie"]
+        assert "Secure" in cookie
+        assert "SameSite=none" in cookie
+
+    @pytest.mark.asyncio
+    async def test_not_secure_over_direct_http(self, saml_env, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        cache = DualCache()
+        request = _fake_request_with_scheme("http")
+        redirect = await SAMLAuthHandler.build_login_redirect(request, cache)
+        cookie = redirect.headers["set-cookie"]
+        assert "Secure" not in cookie
+        assert "SameSite=lax" in cookie
+
+    @pytest.mark.asyncio
+    async def test_secure_behind_trusted_tls_terminating_proxy(self, saml_env, monkeypatch):
+        """THE regression: TLS terminates at a reverse proxy, litellm only sees a
+        plain-HTTP hop, but the cookie must still be marked Secure when the operator
+        has configured a trusted proxy reporting X-Forwarded-Proto: https."""
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        monkeypatch.setattr(
+            "litellm.proxy.proxy_server.general_settings",
+            {"use_x_forwarded_for": True, "mcp_trusted_proxy_ranges": ["10.0.0.0/8"]},
+        )
+        cache = DualCache()
+        request = _fake_request_with_scheme(
+            "http", headers={"X-Forwarded-Proto": "https"}, client_host="10.0.0.5"
+        )
+        redirect = await SAMLAuthHandler.build_login_redirect(request, cache)
+        cookie = redirect.headers["set-cookie"]
+        assert "Secure" in cookie
+
+    @pytest.mark.asyncio
+    async def test_untrusted_spoofed_forwarded_proto_is_ignored(self, saml_env, monkeypatch):
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+        cache = DualCache()
+        request = _fake_request_with_scheme(
+            "http", headers={"X-Forwarded-Proto": "https"}, client_host="203.0.113.5"
+        )
+        redirect = await SAMLAuthHandler.build_login_redirect(request, cache)
+        cookie = redirect.headers["set-cookie"]
+        assert "Secure" not in cookie
diff --git a/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py b/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py
index e648bd09734..dd8c752a868 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py
@@ -7604,6 +7604,112 @@ class TestPKCEStateCookieBinding:
         assert cookie_str is not None
         assert "Secure" not in cookie_str
 
+    @pytest.mark.asyncio
+    async def test_redirect_response_sets_secure_flag_behind_trusted_tls_terminating_proxy(
+        self, monkeypatch
+    ):
+        """Regression: litellm sees a plain-HTTP hop when TLS terminates at a reverse
+        proxy. The Secure flag must still be set when the direct peer is a configured
+        trusted proxy and it reports X-Forwarded-Proto: https -- but NOT from an
+        unconfigured/untrusted caller spoofing the same header (see the sibling test
+        below)."""
+        from fastapi.responses import RedirectResponse
+
+        from litellm.proxy.management_endpoints.ui_sso import (
+            SSOAuthenticationHandler,
+        )
+
+        mock_redirect = RedirectResponse(
+            url="http://idp.internal/authorize?state=behind-proxy-state"
+        )
+        mock_generic_sso = MagicMock()
+        mock_generic_sso.__enter__ = MagicMock(return_value=mock_generic_sso)
+        mock_generic_sso.__exit__ = MagicMock(return_value=None)
+        mock_generic_sso.get_login_redirect = AsyncMock(return_value=mock_redirect)
+
+        proxied_request = MagicMock(spec=Request)
+        proxied_request.url.scheme = "http"
+        proxied_request.headers = {"X-Forwarded-Proto": "https"}
+        proxied_request.client = MagicMock()
+        proxied_request.client.host = "10.0.0.5"
+
+        monkeypatch.setattr(
+            "litellm.proxy.proxy_server.general_settings",
+            {"use_x_forwarded_for": True, "mcp_trusted_proxy_ranges": ["10.0.0.0/8"]},
+        )
+
+        with patch.dict(
+            os.environ,
+            {
+                "GENERIC_CLIENT_STATE": "behind-proxy-state",
+                "GENERIC_CLIENT_USE_PKCE": "true",
+            },
+        ):
+            response = await SSOAuthenticationHandler.get_generic_sso_redirect_response(
+                generic_sso=mock_generic_sso,
+                state=None,
+                generic_authorization_endpoint="http://idp.internal/authorize",
+                request=proxied_request,
+            )
+
+        cookie_headers = response.headers.getlist("set-cookie")
+        cookie_str = next(
+            (c for c in cookie_headers if "litellm_oauth_state=" in c), None
+        )
+        assert cookie_str is not None
+        assert "Secure" in cookie_str
+
+    @pytest.mark.asyncio
+    async def test_redirect_response_ignores_spoofed_forwarded_proto_without_trust_config(
+        self, monkeypatch
+    ):
+        """The same X-Forwarded-Proto: https header must NOT flip Secure on when no
+        trusted-proxy config is present -- honoring it unconditionally would let any
+        client spoof the header and would not itself be the vulnerability the ticket
+        warns against."""
+        from fastapi.responses import RedirectResponse
+
+        from litellm.proxy.management_endpoints.ui_sso import (
+            SSOAuthenticationHandler,
+        )
+
+        mock_redirect = RedirectResponse(
+            url="http://idp.internal/authorize?state=spoofed-state"
+        )
+        mock_generic_sso = MagicMock()
+        mock_generic_sso.__enter__ = MagicMock(return_value=mock_generic_sso)
+        mock_generic_sso.__exit__ = MagicMock(return_value=None)
+        mock_generic_sso.get_login_redirect = AsyncMock(return_value=mock_redirect)
+
+        spoofed_request = MagicMock(spec=Request)
+        spoofed_request.url.scheme = "http"
+        spoofed_request.headers = {"X-Forwarded-Proto": "https"}
+        spoofed_request.client = MagicMock()
+        spoofed_request.client.host = "203.0.113.5"
+
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+
+        with patch.dict(
+            os.environ,
+            {
+                "GENERIC_CLIENT_STATE": "spoofed-state",
+                "GENERIC_CLIENT_USE_PKCE": "true",
+            },
+        ):
+            response = await SSOAuthenticationHandler.get_generic_sso_redirect_response(
+                generic_sso=mock_generic_sso,
+                state=None,
+                generic_authorization_endpoint="http://idp.internal/authorize",
+                request=spoofed_request,
+            )
+
+        cookie_headers = response.headers.getlist("set-cookie")
+        cookie_str = next(
+            (c for c in cookie_headers if "litellm_oauth_state=" in c), None
+        )
+        assert cookie_str is not None
+        assert "Secure" not in cookie_str
+
     @pytest.mark.asyncio
     async def test_pkce_callback_rejects_missing_cookie(self):
         """When PKCE is enabled and a code_verifier is in the cache, the
@@ -8586,6 +8692,24 @@ class TestSameOriginReturnPath:
         assert _is_same_origin_return_path("") is False
 
 
+def _make_https_request() -> Request:
+    request = MagicMock(spec=Request)
+    request.url.scheme = "https"
+    request.headers = {}
+    request.client = MagicMock()
+    request.client.host = "203.0.113.5"
+    return request
+
+
+def _make_http_request() -> Request:
+    request = MagicMock(spec=Request)
+    request.url.scheme = "http"
+    request.headers = {}
+    request.client = MagicMock()
+    request.client.host = "203.0.113.5"
+    return request
+
+
 class TestPersistReturnToCookieSharedHelper:
     """The single shared return_to helper used by EVERY sign-in branch (SSO / Okta / generic AND the
     username/password form). It must be best-effort and NEVER raise — a bad return_to can never block
@@ -8603,7 +8727,7 @@ class TestPersistReturnToCookieSharedHelper:
 
         monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
         resp = Response()
-        _persist_return_to_cookie(resp, "/mcp/authorize?client_id=llm_dcrc_abc")
+        _persist_return_to_cookie(resp, "/mcp/authorize?client_id=llm_dcrc_abc", _make_https_request())
         assert "litellm_cp_return_to=" in self._cookie(resp)
 
     def test_bad_absolute_with_control_plane_configured_does_not_raise_and_is_not_stored(self, monkeypatch):
@@ -8617,7 +8741,7 @@ class TestPersistReturnToCookieSharedHelper:
             "litellm.proxy.proxy_server.general_settings", {"control_plane_url": "https://cp.example.com"}
         )
         resp = Response()
-        _persist_return_to_cookie(resp, "https://evil.example.com/steal")  # must not raise
+        _persist_return_to_cookie(resp, "https://evil.example.com/steal", _make_https_request())  # must not raise
         assert "litellm_cp_return_to=" not in self._cookie(resp)
 
     def test_none_return_to_is_a_noop(self):
@@ -8626,7 +8750,7 @@ class TestPersistReturnToCookieSharedHelper:
         from litellm.proxy.management_endpoints.ui_sso import _persist_return_to_cookie
 
         resp = Response()
-        _persist_return_to_cookie(resp, None)
+        _persist_return_to_cookie(resp, None, _make_https_request())
         assert "litellm_cp_return_to=" not in self._cookie(resp)
 
     def test_control_plane_matching_absolute_is_stored(self, monkeypatch):
@@ -8638,5 +8762,126 @@ class TestPersistReturnToCookieSharedHelper:
             "litellm.proxy.proxy_server.general_settings", {"control_plane_url": "https://cp.example.com"}
         )
         resp = Response()
-        _persist_return_to_cookie(resp, "https://cp.example.com/ui?page=models")
+        _persist_return_to_cookie(resp, "https://cp.example.com/ui?page=models", _make_https_request())
         assert "litellm_cp_return_to=" in self._cookie(resp)
+
+    def test_cookie_is_secure_and_httponly_over_https(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import _persist_return_to_cookie
+
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+        resp = Response()
+        _persist_return_to_cookie(resp, "/mcp/authorize", _make_https_request())
+        cookie = self._cookie(resp)
+        assert "Secure" in cookie
+        assert "HttpOnly" in cookie
+        assert "SameSite=lax" in cookie
+
+    def test_cookie_is_not_secure_over_plain_http_direct(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import _persist_return_to_cookie
+
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+        resp = Response()
+        _persist_return_to_cookie(resp, "/mcp/authorize", _make_http_request())
+        assert "Secure" not in self._cookie(resp)
+
+    def test_cookie_is_secure_behind_trusted_tls_terminating_proxy(self, monkeypatch):
+        """Regression for the reported bug: TLS terminates at a reverse proxy, litellm only
+        sees a plain-HTTP hop, but a trusted X-Forwarded-Proto: https must still mark the
+        cookie Secure."""
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import _persist_return_to_cookie
+
+        monkeypatch.setattr(
+            "litellm.proxy.proxy_server.general_settings",
+            {"use_x_forwarded_for": True, "mcp_trusted_proxy_ranges": ["10.0.0.0/8"]},
+        )
+        resp = Response()
+        request = _make_http_request()
+        request.client.host = "10.0.0.5"
+        request.headers = {"X-Forwarded-Proto": "https"}
+        _persist_return_to_cookie(resp, "/mcp/authorize", request)
+        assert "Secure" in self._cookie(resp)
+
+
+class TestSessionTokenCookie:
+    """Regression tests for the ``token`` session cookie set by every sign-in path
+    (username/password login, SSO callback, the CLI /v2, /v3 login exchange helpers).
+    It was previously set with no Secure/HttpOnly/SameSite attributes at all -- always
+    sent over plain HTTP and readable by any script on the page. HttpOnly must stay off
+    deliberately: the dashboard reads this cookie via document.cookie."""
+
+    @staticmethod
+    def _cookie(resp) -> str:
+        return resp.headers.get("set-cookie", "")
+
+    def test_secure_over_direct_https(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        resp = Response()
+        set_session_token_cookie(resp, _make_https_request(), "jwt-token-value")
+        cookie = self._cookie(resp)
+        assert "token=jwt-token-value" in cookie
+        assert "Secure" in cookie
+        assert "SameSite=lax" in cookie
+        assert "HttpOnly" not in cookie
+
+    def test_not_secure_over_direct_http(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        resp = Response()
+        set_session_token_cookie(resp, _make_http_request(), "jwt-token-value")
+        assert "Secure" not in self._cookie(resp)
+
+    def test_secure_behind_trusted_tls_terminating_proxy(self, monkeypatch):
+        """THE regression: TLS terminates at a reverse proxy, litellm only sees a
+        plain-HTTP hop, but the session cookie must still be marked Secure when the
+        operator has configured a trusted proxy that reports X-Forwarded-Proto: https."""
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        monkeypatch.setattr(
+            "litellm.proxy.proxy_server.general_settings",
+            {"use_x_forwarded_for": True, "mcp_trusted_proxy_ranges": ["10.0.0.0/8"]},
+        )
+        request = _make_http_request()
+        request.client.host = "10.0.0.5"
+        request.headers = {"X-Forwarded-Proto": "https"}
+        resp = Response()
+        set_session_token_cookie(resp, request, "jwt-token-value")
+        assert "Secure" in self._cookie(resp)
+
+    def test_untrusted_spoofed_forwarded_proto_is_ignored(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
+        monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+        request = _make_http_request()
+        request.headers = {"X-Forwarded-Proto": "https"}
+        resp = Response()
+        set_session_token_cookie(resp, request, "jwt-token-value")
+        assert "Secure" not in self._cookie(resp)
+
+    def test_proxy_base_url_https_overrides_literal_http_scheme(self, monkeypatch):
+        from fastapi import Response
+
+        from litellm.proxy.management_endpoints.ui_sso import set_session_token_cookie
+
+        monkeypatch.setenv("PROXY_BASE_URL", "https://litellm.example.com")
+        resp = Response()
+        set_session_token_cookie(resp, _make_http_request(), "jwt-token-value")
+        assert "Secure" in self._cookie(resp)
diff --git a/tests/test_litellm/proxy/test_proxy_server.py b/tests/test_litellm/proxy/test_proxy_server.py
index 5f692f8f109..4ed6a468371 100644
--- a/tests/test_litellm/proxy/test_proxy_server.py
+++ b/tests/test_litellm/proxy/test_proxy_server.py
@@ -148,6 +148,72 @@ def test_login_v2_returns_redirect_url_and_sets_cookie(monkeypatch):
     assert mock_jwt_encode.call_args.kwargs == {"algorithm": "HS256"}
 
 
+def _mock_login_v2_deps(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(
+        "litellm.proxy.auth.login_utils.authenticate_user",
+        AsyncMock(return_value={"user_id": "test-user"}),
+    )
+    monkeypatch.setattr(
+        "litellm.proxy.auth.login_utils.create_ui_token_object",
+        MagicMock(return_value={"user_id": "test-user"}),
+    )
+    monkeypatch.setattr("jwt.encode", MagicMock(return_value="signed-token"))
+    monkeypatch.setattr("litellm.proxy.proxy_server.master_key", "test-master-key")
+    monkeypatch.setattr("litellm.proxy.proxy_server.premium_user", False)
+    monkeypatch.setattr("litellm.proxy.proxy_server.prisma_client", MagicMock())
+    monkeypatch.setattr("litellm.proxy.utils.get_server_root_path", lambda: "")
+    monkeypatch.setattr("litellm.proxy.utils.get_proxy_base_url", lambda: None)
+    monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+
+
+def test_login_v2_sets_secure_cookie_over_direct_https(monkeypatch):
+    """Regression: the token cookie previously carried no Secure/HttpOnly/SameSite
+    attributes at all, so it was always sent over plain HTTP."""
+    _mock_login_v2_deps(monkeypatch)
+    monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+
+    client = TestClient(app, base_url="https://testserver")
+    response = client.post("/v2/login", json={"username": "alice", "password": "secret"})
+
+    assert response.status_code == 200
+    cookie = response.headers.get("set-cookie")
+    assert "Secure" in cookie
+    assert "HttpOnly" not in cookie  # deliberate: the dashboard reads this cookie via JS
+    assert "samesite=lax" in cookie.lower()
+
+
+def test_login_v2_does_not_set_secure_cookie_over_direct_http(monkeypatch):
+    _mock_login_v2_deps(monkeypatch)
+    monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", {})
+
+    client = TestClient(app, base_url="http://testserver")
+    response = client.post("/v2/login", json={"username": "alice", "password": "secret"})
+
+    assert response.status_code == 200
+    assert "Secure" not in response.headers.get("set-cookie")
+
+
+def test_login_v2_sets_secure_cookie_behind_trusted_tls_terminating_proxy(monkeypatch):
+    """THE regression: litellm only sees a plain-HTTP hop when TLS terminates at a
+    reverse proxy, but the token cookie must still be Secure when the direct peer is
+    a configured trusted proxy reporting X-Forwarded-Proto: https."""
+    _mock_login_v2_deps(monkeypatch)
+    monkeypatch.setattr(
+        "litellm.proxy.proxy_server.general_settings",
+        {"use_x_forwarded_for": True, "mcp_trusted_proxy_ranges": ["10.0.0.0/8"]},
+    )
+
+    client = TestClient(app, base_url="http://testserver", client=("10.0.0.5", 50000))
+    response = client.post(
+        "/v2/login",
+        json={"username": "alice", "password": "secret"},
+        headers={"X-Forwarded-Proto": "https"},
+    )
+
+    assert response.status_code == 200
+    assert "Secure" in response.headers.get("set-cookie")
+
+
 def test_login_v2_returns_json_on_proxy_exception(monkeypatch):
     """Test that /v2/login returns JSON error when ProxyException is raised"""
     from litellm.proxy._types import ProxyErrorTypes, ProxyException
@@ -356,6 +422,51 @@ def test_login_v3_exchange_happy_path(monkeypatch):
     assert exchange_response.cookies.get("token") == "signed-token"
 
 
+def test_login_v3_exchange_sets_secure_cookie_behind_trusted_tls_terminating_proxy(monkeypatch):
+    """Regression: /v3/login/exchange's token cookie must be Secure behind a trusted
+    TLS-terminating reverse proxy even though litellm only sees a plain-HTTP hop."""
+    mock_prisma_client = MagicMock()
+    monkeypatch.setattr(
+        "litellm.proxy.auth.login_utils.authenticate_user",
+        AsyncMock(return_value={"user_id": "test-user"}),
+    )
+    monkeypatch.setattr(
+        "litellm.proxy.auth.login_utils.create_ui_token_object",
+        MagicMock(return_value={"user_id": "test-user"}),
+    )
+    monkeypatch.setattr("jwt.encode", MagicMock(return_value="signed-token"))
+    monkeypatch.setattr("litellm.proxy.proxy_server.master_key", "test-master-key")
+    monkeypatch.setattr(
+        "litellm.proxy.proxy_server.general_settings",
+        {
+            "control_plane_url": "https://cp.example.com",
+            "use_x_forwarded_for": True,
+            "mcp_trusted_proxy_ranges": ["10.0.0.0/8"],
+        },
+    )
+    monkeypatch.setattr("litellm.proxy.proxy_server.premium_user", False)
+    monkeypatch.setattr("litellm.proxy.proxy_server.prisma_client", mock_prisma_client)
+    mock_config = MagicMock()
+    mock_config.worker_registry = []
+    monkeypatch.setattr("litellm.proxy.proxy_server.proxy_config", mock_config)
+    monkeypatch.setattr("litellm.proxy.utils.get_server_root_path", lambda: "")
+    monkeypatch.setattr("litellm.proxy.utils.get_proxy_base_url", lambda: None)
+    monkeypatch.delenv("PROXY_BASE_URL", raising=False)
+
+    client = TestClient(app, base_url="http://testserver", client=("10.0.0.5", 50000))
+
+    login_response = client.post("/v3/login", json={"username": "alice", "password": "secret"})
+    code = login_response.json()["code"]
+
+    exchange_response = client.post(
+        "/v3/login/exchange",
+        json={"code": code},
+        headers={"X-Forwarded-Proto": "https"},
+    )
+    assert exchange_response.status_code == 200
+    assert "Secure" in exchange_response.headers.get("set-cookie")
+
+
 def test_login_v3_exchange_single_use(monkeypatch):
     """Code can only be redeemed once."""
     mock_prisma_client = MagicMock()