Jellyfin up to 10.11.6 Query Parameter StreamingHelpers.cs ParseStreamOptions argument injection

Summaryinfo

A vulnerability was found in Jellyfin up to 10.11.6. It has been declared as critical. This impacts the function ParseStreamOptions of the file StreamingHelpers.cs of the component Query Parameter Handler. Such manipulation of the argument StreamOptions leads to argument injection. This vulnerability is listed as CVE-2026-35033. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Jellyfin up to 10.11.6. Affected by this issue is the function ParseStreamOptions of the file StreamingHelpers.cs of the component Query Parameter Handler. The manipulation of the argument StreamOptions with an unknown input leads to a argument injection vulnerability. Using CWE to declare the problem leads to CWE-88. The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain an unauthenticated arbitrary file read vulnerability via ffmpeg argument injection through the StreamOptions query parameter parsing mechanism. The ParseStreamOptions method in StreamingHelpers.cs adds any lowercase query parameter to a dictionary without validation, bypassing the RegularExpression attribute on the level controller parameter, and the unsanitized value is concatenated directly into the ffmpeg command line. By injecting a drawtext filter with a textfile argument, an attacker can read arbitrary server files such as /etc/shadow and exfiltrate their contents as text rendered in the video stream response. The vulnerable /Videos/{itemId}/stream endpoint has no Authorize attribute, making this exploitable without authentication, though item GUIDs are pseudorandom and require an authenticated user to obtain. This issue has been fixed in version 10.11.7.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-35033 since 03/31/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 10.11.7 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Name

• Jellyfin

Version

• 10.11.0
• 10.11.1
• 10.11.2
• 10.11.3
• 10.11.4
• 10.11.5
• 10.11.6

Website

• Product: https://github.com/jellyfin/jellyfin/

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