From bce6d2893f88eb6d3846ada21ff73dd840ea5ca8 Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Wed, 28 Oct 2026 21:47:31 -0700
Subject: [PATCH] fix(router): validate strict litellm params through a helper
 so star imports cannot re-bind a public Final

---
 litellm/main.py         |  6 ++----
 litellm/router.py       |  8 ++++----
 litellm/types/router.py | 13 +++++++++++--
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/litellm/main.py b/litellm/main.py
index ec024eee433..44a595cbc43 100644
--- a/litellm/main.py
+++ b/litellm/main.py
@@ -154,7 +154,7 @@ from litellm.types.completion import (
 )
 from litellm.types.litellm_params import ControlOptions, RetryStrategy
 from litellm.types.llms.openai import AllMessageValues
-from litellm.types.router import STRICT_LITELLM_PARAMS, GenericLiteLLMParams
+from litellm.types.router import GenericLiteLLMParams, validate_litellm_params_strictly
 from litellm.types.utils import (
     BaseUrlRoutingHint,
     CustomPricingLiteLLMParams,
@@ -401,9 +401,7 @@ class _SupplementalProviderParams:
 def _supplemental_provider_params(kwargs: Mapping[str, object], model: str) -> _SupplementalProviderParams:
     supplemental: Final = {key: kwargs[key] for key in SUPPLEMENTAL_KWARGS_KEYS if key in kwargs}
     try:
-        return _SupplementalProviderParams(
-            params=GenericLiteLLMParams.model_validate(supplemental, context=STRICT_LITELLM_PARAMS)
-        )
+        return _SupplementalProviderParams(params=validate_litellm_params_strictly(GenericLiteLLMParams, supplemental))
     except ValidationError as error:
         invalid: Final = tuple(detail for detail in error.errors() if detail["loc"])
         invalid_keys: Final = frozenset(str(detail["loc"][0]) for detail in invalid)
diff --git a/litellm/router.py b/litellm/router.py
index 2a614eaf086..3a5a4c1a6d9 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -414,7 +414,6 @@ from litellm.types.llms.openai import (
 )
 from litellm.types.router import (
     CONFIGURABLE_CLIENTSIDE_AUTH_PARAMS,
-    STRICT_LITELLM_PARAMS,
     VALID_LITELLM_ENVIRONMENTS,
     AlertingConfig,
     AllowedFailsPolicy,
@@ -451,6 +450,7 @@ from litellm.types.router import (
     SearchToolTypedDict,
     TaggedPreRoutingStrategy,
     holds_secret_pointer,
+    validate_litellm_params_strictly,
 )
 from litellm.types.services import ServiceTypes
 from litellm.types.utils import (
@@ -704,7 +704,7 @@ def _malformed_request_params_the_deployment_sets(
         if key in request and deployment_params.get(key) is not None
     }
     try:
-        GenericLiteLLMParams.model_validate(overrides, context=STRICT_LITELLM_PARAMS)
+        validate_litellm_params_strictly(GenericLiteLLMParams, overrides)
     except ValidationError as error:
         set_defaults: Final = {name: value for name, value in defaults.items() if value is not None}
         policy: Final = drop_policy({**deployment_params, **set_defaults, **request})
@@ -10628,8 +10628,8 @@ class Router:
             merged_params: Final[Mapping[str, object]] = (
                 _litellm_params if zeroed_pricing is None else MappingProxyType({**_litellm_params, **zeroed_pricing})
             )
-            litellm_params: Final[LiteLLM_Params] = LiteLLM_Params.model_validate(
-                dict(**merged_params), context=STRICT_LITELLM_PARAMS
+            litellm_params: Final[LiteLLM_Params] = validate_litellm_params_strictly(
+                LiteLLM_Params, dict(**merged_params)
             )
             declared_params: Final = _LITELLM_PARAMS_ADAPTER.validate_python(_litellm_params)
             warn_on_provider_credential_mismatch(model_name=_model_name, litellm_params=declared_params)
diff --git a/litellm/types/router.py b/litellm/types/router.py
index 3a559f13cde..87a293fc4d2 100644
--- a/litellm/types/router.py
+++ b/litellm/types/router.py
@@ -24,6 +24,7 @@ from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 import httpx
 from openai import Timeout as SDKTimeout
 from pydantic import (
+    BaseModel,
     BeforeValidator,
     ConfigDict,
     Field,
@@ -530,7 +531,15 @@ def holds_secret_pointer(param_name: str) -> bool:
 
 _RESERVED_INIT_KEYS: Final = frozenset({"self", "params", "__class__"})
 
-STRICT_LITELLM_PARAMS: Final = MappingProxyType({"strict_litellm_params": True})
+_STRICT_LITELLM_PARAMS: Final = MappingProxyType({"strict_litellm_params": True})
+
+_StrictlyValidatedParams: Final = TypeVar("_StrictlyValidatedParams", bound=BaseModel)
+
+
+def validate_litellm_params_strictly(
+    params_model: type[_StrictlyValidatedParams], params: Mapping[str, object]
+) -> _StrictlyValidatedParams:
+    return params_model.model_validate(params, context=_STRICT_LITELLM_PARAMS)
 
 
 def _none_when_malformed_outside_strict_validation(
@@ -539,7 +548,7 @@ def _none_when_malformed_outside_strict_validation(
     try:
         return handler(value)
     except ValidationError:
-        if info.context is STRICT_LITELLM_PARAMS:
+        if info.context is _STRICT_LITELLM_PARAMS:
             raise
         return None