CVE-2026-48793: Jellyfin: Potential FFmpeg argument injection via unescaped subtitle file path
Jellyfin is an open source self hosted media server. Prior to 10.11.10, a potential FFmpeg argument injection vulnerability exists in the subtitle conversion code path. SubtitleEncoder.ConvertTextSubtitleToSrtInternal (SubtitleEncoder.cs, line 382) interpolates the subtitle file path into FFmpeg command-line arguments without calling EncodingUtils.NormalizePath(). On Linux, filenames can contain double-quote characters, which break the argument quoting and allow injection of arbitrary FFmpeg arguments. The vulnerability is reachable without authentication via SubtitleController.GetSubtitle, which has no [Authorize] attribute. An attacker who can place a file in a Jellyfin media library directory (shared NAS, Samba share, guest upload) can achieve arbitrary file write on the server and information disclosure. This vulnerability is fixed in 10.11.10.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Jellyfinto a version that resolves this vulnerability.Fixed in 10.11.10 - Compensating control
Restrict write access to the Jellyfin media library directories (e.g., limit/disable guest uploads on the shared NAS/Samba share) so attackers cannot place crafted subtitle files with double-quote characters into the library path.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-48793?
CVE-2026-48793 has a severity rating of high, with a score of 8.8.
How do I fix CVE-2026-48793?
To fix CVE-2026-48793, update Jellyfin to version 10.11.10 or later.
What software is affected by CVE-2026-48793?
CVE-2026-48793 affects Jellyfin, specifically versions prior to 10.11.10.
What type of vulnerability is CVE-2026-48793?
CVE-2026-48793 is a potential FFmpeg argument injection vulnerability related to unescaped subtitle file paths.
How does CVE-2026-48793 affect users?
CVE-2026-48793 could potentially allow an attacker to execute arbitrary FFmpeg commands by manipulating subtitle file paths.