fix(videos): encode the variant query param

``variant`` is user-controlled (passed through from
``litellm.video_content(variant=...)``) and was interpolated raw into
the URL query string.  A value like ``thumbnail&extra=1`` would inject
additional query parameters into the upstream request — the same
class of issue this PR's path-segment encoding addresses.  Wrap the
value in ``quote(value, safe="")`` so ``&`` / ``=`` / ``#`` cannot
terminate the ``variant`` value or open a new parameter.

Adds a regression test asserting that a malicious ``thumbnail&extra=1``
ends up percent-encoded in the URL, and that the legitimate
``thumbnail`` value still round-trips cleanly.

litellm/llms/openai/videos/transformation.py

@@ -1,6 +1,7 @@
 import mimetypes
 from io import BufferedReader, BytesIO
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union, cast
+from urllib.parse import quote
 
 import httpx
 from httpx._types import RequestFiles
@@ -228,7 +229,11 @@ class OpenAIVideoConfig(BaseVideoConfig):
         # Construct the URL for video content download
         url = f"{api_base.rstrip('/')}/{encoded_video_id}/content"
         if variant is not None:
-            url = f"{url}?variant={variant}"
+            # Encode the user-controlled ``variant`` so a value like
+            # ``thumbnail&extra=1`` cannot inject additional query params
+            # into the upstream request — same hardening rationale as the
+            # path-segment encoding above.
+            url = f"{url}?variant={quote(variant, safe='')}"
 
         # No additional data needed for GET content request
         data: Dict[str, Any] = {}

tests/test_litellm/llms/openai/videos/test_openai_video_transformation.py

@@ -20,6 +20,34 @@ def test_video_content_request_encodes_video_id_path_segment():
     assert params == {}
 
 
+def test_video_content_request_encodes_variant_query_param():
+    """``variant`` is user-controlled and was previously interpolated raw
+    into the query string.  A value like ``thumbnail&extra=1`` would
+    inject additional query parameters into the upstream request."""
+    config = OpenAIVideoConfig()
+
+    url, _ = config.transform_video_content_request(
+        video_id="vid_123",
+        api_base="https://api.openai.com/v1/videos",
+        litellm_params=GenericLiteLLMParams(),
+        headers={},
+        variant="thumbnail&extra=1",
+    )
+
+    # ``&`` and ``=`` must be percent-encoded so they cannot terminate
+    # the ``variant`` value or open a new query parameter.
+    assert "?variant=thumbnail%26extra%3D1" in url
+    # Sanity: the legitimate "thumbnail" value still round-trips cleanly.
+    url2, _ = config.transform_video_content_request(
+        video_id="vid_123",
+        api_base="https://api.openai.com/v1/videos",
+        litellm_params=GenericLiteLLMParams(),
+        headers={},
+        variant="thumbnail",
+    )
+    assert url2.endswith("?variant=thumbnail")
+
+
 def test_wrapped_character_id_is_decoded_then_encoded_as_path_segment():
     config = OpenAIVideoConfig()
     character_id = encode_character_id_with_provider(