chore(utils): mask credentials embedded in connection URLs

Add mask_url_credentials() to redact the password in a connection-URL's
userinfo (e.g. redis://:pw@host -> redis://:****@host) while preserving
scheme, host, and port. Field-name masking misses passwords smuggled into
URL values; this closes that gap for reuse across the proxy read endpoints.

litellm/litellm_core_utils/sensitive_data_masker.py

@@ -1,5 +1,7 @@
+import re
 from collections.abc import Mapping
 from typing import Any, Dict, List, Optional, Set
+from urllib.parse import urlsplit, urlunsplit
 
 from litellm.constants import DEFAULT_MAX_RECURSE_DEPTH_SENSITIVE_DATA_MASKER
 
@@ -177,6 +179,38 @@ def mask_sensitive_keys(
     return masked
 
 
+# A connection URL whose authority contains userinfo, e.g. ``redis://u:p@host``.
+# Requires the ``@`` to appear before any path/query/fragment so plain URLs
+# without credentials (``https://host/path?x=@y``) are left untouched.
+_URL_WITH_USERINFO = re.compile(r"^[a-zA-Z][a-zA-Z0-9+.\-]*://[^/?#\s]*@")
+
+
+def mask_url_credentials(value: Any) -> Any:
+    """Redact a password embedded in a connection URL's userinfo while keeping
+    the scheme, host, and port intact so the field stays diagnostically useful.
+
+    ``redis://user:pass@host:6379`` -> ``redis://user:****@host:6379``
+    ``rediss://:pass@host``         -> ``rediss://:****@host``
+
+    Strings without credentialed userinfo, and non-strings, are returned
+    unchanged.
+    """
+    if not isinstance(value, str) or not _URL_WITH_USERINFO.match(value):
+        return value
+    try:
+        parts = urlsplit(value)
+    except ValueError:
+        return value
+    if parts.password is None:
+        return value
+    netloc = (
+        f"{parts.username or ''}:{_default_masker.mask_char * 4}@{parts.hostname or ''}"
+    )
+    if parts.port is not None:
+        netloc += f":{parts.port}"
+    return urlunsplit((parts.scheme, netloc, parts.path, parts.query, parts.fragment))
+
+
 # Usage example:
 """
 masker = SensitiveDataMasker()

tests/test_litellm/litellm_core_utils/test_sensitive_data_masker.py

@@ -154,3 +154,39 @@ def test_cost_per_token_fields_not_masked():
     # Actual secrets must still be masked
     assert "*" in masked["api_key"]
     assert "*" in masked["access_token"]
+
+
+from litellm.litellm_core_utils.sensitive_data_masker import mask_url_credentials
+
+
+def test_mask_url_credentials_redacts_password_only():
+    """A password embedded in a connection URL is redacted while scheme/host/
+    port stay intact, so the value is still diagnostically useful."""
+    assert (
+        mask_url_credentials("redis://:supersecretpw@redis.internal:6379")
+        == "redis://:****@redis.internal:6379"
+    )
+    assert (
+        mask_url_credentials("rediss://user:supersecretpw@host.example:6380/0")
+        == "rediss://user:****@host.example:6380/0"
+    )
+    # The plaintext password must never survive.
+    assert "supersecretpw" not in mask_url_credentials(
+        "redis://user:supersecretpw@host:6379"
+    )
+
+
+def test_mask_url_credentials_leaves_non_credentialed_values_untouched():
+    """URLs without a password, non-URL strings, and the '@' appearing only in
+    a path/query are all returned verbatim."""
+    assert (
+        mask_url_credentials("redis://redis.internal:6379")
+        == "redis://redis.internal:6379"
+    )
+    assert mask_url_credentials("redis://user@host:6379") == "redis://user@host:6379"
+    assert mask_url_credentials("https://api.example.com/v1?to=a@b.com") == (
+        "https://api.example.com/v1?to=a@b.com"
+    )
+    assert mask_url_credentials("plain-secret-value") == "plain-secret-value"
+    assert mask_url_credentials(None) is None
+    assert mask_url_credentials(1234) == 1234