Validate requested user id (#8812)

1 files changed, 3 insertions, 2 deletions

diff --git a/Jellyfin.Api/Controllers/VideosController.cs b/Jellyfin.Api/Controllers/VideosController.cs
index 3a61367f7..c0ec646ed 100644
--- a/Jellyfin.Api/Controllers/VideosController.cs
+++ b/Jellyfin.Api/Controllers/VideosController.cs
@@ -104,12 +104,13 @@ public class VideosController : BaseJellyfinApiController
     [ProducesResponseType(StatusCodes.Status200OK)]
     public ActionResult<QueryResult<BaseItemDto>> GetAdditionalPart([FromRoute, Required] Guid itemId, [FromQuery] Guid? userId)
     {
-        var user = userId is null || userId.Value.Equals(default)
+        userId = RequestHelpers.GetUserId(User, userId);
+        var user = userId.Value.Equals(default)
             ? null
             : _userManager.GetUserById(userId.Value);
 
         var item = itemId.Equals(default)
-            ? (userId is null || userId.Value.Equals(default)
+            ? (userId.Value.Equals(default)
                 ? _libraryManager.RootFolder
                 : _libraryManager.GetUserRootFolder())
             : _libraryManager.GetItemById(itemId);