diff --git a/litellm/proxy/management_endpoints/ui_sso.py b/litellm/proxy/management_endpoints/ui_sso.py
index cd88e9105fa..304a1b47896 100644
--- a/litellm/proxy/management_endpoints/ui_sso.py
+++ b/litellm/proxy/management_endpoints/ui_sso.py
@@ -2619,6 +2619,8 @@ class SSOAuthenticationHandler:
                     # cache misses so operators can investigate the correct root cause.
                     if _empty_value_in_dict:
                         # Dict format was correct but code_verifier was empty/null.
+                        # Best-effort cleanup: remove the corrupt entry before failing.
+                        await SSOAuthenticationHandler._delete_pkce_verifier(cache_key)
                         raise ProxyException(
                             message=(
                                 f"PKCE verifier for state '{state}' was found in cache but "
@@ -2630,6 +2632,8 @@ class SSOAuthenticationHandler:
                         )
                     elif cached_data is not None:
                         # Cache had data but in an unrecognised format (e.g. corrupt Redis value).
+                        # Best-effort cleanup: remove the corrupt entry before failing.
+                        await SSOAuthenticationHandler._delete_pkce_verifier(cache_key)
                         verbose_proxy_logger.error(
                             "PKCE verifier for state '%s' has an unrecognized format (type=%s); "
                             "treating as a cache miss. Investigate the cached value — it may be "
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 5b05e16cf72..602ec6afcaf 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_ui_sso.py
@@ -3819,6 +3819,8 @@ class TestPKCEFunctionality:
 
         assert "cache" in exc_info.value.message.lower() or "verifier" in exc_info.value.message.lower() or "format" in exc_info.value.message.lower()
         assert str(exc_info.value.code) == "401"
+        # Strict mode should also clean up the corrupt cache entry before raising
+        mock_cache.async_delete_cache.assert_called_once()
 
     @pytest.mark.asyncio
     async def test_pkce_cache_miss_non_strict_logs_warning_and_continues(self, caplog):