From 142ba42883f7713b7fcd9a82b170f86b2c933c4b Mon Sep 17 00:00:00 2001
From: MBR-0001 <55142207+MBR-0001@users.noreply.github.com>
Date: Mon, 6 Apr 2026 05:19:32 -0400
Subject: [PATCH] Backport pull request #16539 from jellyfin/release-10.11.z

Fix subtitle saving

Original-merge: f51c63e244436944d5269085a1bed1e56db7a78e

Merged-by: nielsvanvelzen <nielsvanvelzen@users.noreply.github.com>

Backported-by: Bond_009 <bond.009@outlook.com>
---
 MediaBrowser.Providers/Subtitles/SubtitleManager.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/MediaBrowser.Providers/Subtitles/SubtitleManager.cs b/MediaBrowser.Providers/Subtitles/SubtitleManager.cs
index ae5e1090ad..420dd39a48 100644
--- a/MediaBrowser.Providers/Subtitles/SubtitleManager.cs
+++ b/MediaBrowser.Providers/Subtitles/SubtitleManager.cs
@@ -221,6 +221,11 @@ namespace MediaBrowser.Providers.Subtitles
 
         private async Task TrySaveToFiles(Stream stream, List<string> savePaths, Video video, string extension)
         {
+            if (!_allowedSubtitleFormats.Contains(extension, StringComparison.OrdinalIgnoreCase))
+            {
+                throw new ArgumentException($"Invalid subtitle format: {extension}");
+            }
+
             List<Exception>? exs = null;
 
             foreach (var savePath in savePaths)