CVE-2026-119550 in Jellyfin
Summary
by MITRE • 10/30/2026
Jellyfin through 12.4 contains an information disclosure vulnerability in PlaylistsController.GetPlaylist that allows authenticated users to read hidden item IDs by requesting public or shared playlists. Restricted or parental-controlled users can obtain GUIDs of inaccessible library items from unfiltered playlist ItemIds and then stream that hidden media.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified within Jellyfin versions up to 12.4 represents a significant flaw in the access control logic governing playlist retrieval operations, specifically affecting the PlaylistsController.GetPlaylist endpoint. This issue stems from an improper restriction of information exposure where the application fails to adequately filter or validate items contained within playlists before returning them to authenticated clients. While Jellyfin implements granular permission systems designed to restrict user access based on roles and parental controls, this specific implementation flaw allows these security boundaries to be bypassed through a mechanism that relies on playlist metadata rather than direct item ID requests. The core technical failure lies in the backend logic which aggregates items from playlists without cross-referencing each individual ItemId against the requesting user's current permission set or library access restrictions. Consequently, when an authenticated user queries for public or shared playlists, the server returns a comprehensive list of all media identifiers associated with that playlist, regardless of whether those specific media files are accessible to the requester under normal circumstances.
This architectural oversight creates a direct pathway for information disclosure and subsequent unauthorized data access. By exploiting this flaw, an attacker who possesses valid authentication credentials can enumerate hidden or restricted content simply by inspecting the ItemIds returned in the JSON response from the GetPlaylist endpoint. These identifiers typically include Globally Unique Identifiers (GUIDs) that are essential for constructing direct streaming URLs or API calls to retrieve media data. In a properly secured system, requests for items outside the user's permission scope should result in an access denied error or the omission of those specific IDs from the response payload. However, due to the lack of filtering at the playlist aggregation stage, restricted users can extract these GUIDs and subsequently issue direct playback requests using them. This effectively circumvents parental controls and library restriction policies that are intended to limit content visibility based on age ratings, user roles, or other security attributes defined by the system administrator.
The operational impact of this vulnerability is substantial for environments relying on Jellyfin for media distribution with strict access control requirements. For home users employing parental controls, this flaw allows children or unauthorized viewers to bypass restrictions and stream mature or prohibited content simply by accessing a shared playlist that contains such items. In enterprise or multi-user scenarios where different user groups have varying levels of data sensitivity, this vulnerability enables lateral movement in terms of information access. An authenticated user with low privileges can escalate their effective permissions regarding media consumption without needing elevated system rights or exploiting additional vulnerabilities. This undermines the fundamental principle of least privilege and compromises the integrity of the content filtering mechanisms that administrators rely on to manage digital assets securely. The ability to stream hidden media means that confidentiality controls are rendered ineffective for any playlist containing restricted items, leading to potential compliance violations in regulated industries where data access must be strictly audited and controlled.
To mitigate this vulnerability, immediate action is required by upgrading the Jellyfin installation to a version later than 12.4, which includes patches addressing these access control checks. Until an upgrade can be performed, administrators should consider implementing network-level controls such as firewall rules or reverse proxy configurations that restrict direct API access to sensitive endpoints if possible, although this may impact legitimate functionality. Additionally, reviewing playlist contents is advisable; removing restricted items from playlists shared with broader audiences reduces the attack surface by eliminating the vector through which hidden GUIDs are exposed. It is also recommended to enforce strong authentication policies and monitor logs for unusual patterns of media playback requests originating from users who do not typically access certain libraries. Long-term remediation involves ensuring that all API endpoints undergo rigorous security testing focused on authorization checks, particularly those involving aggregation functions like playlist retrieval, to ensure that every item returned has been validated against the requester's specific permissions before transmission. This aligns with industry standards such as CWE-200 for Information Exposure and addresses weaknesses related to improper access control found in common weakness enumerations regarding broken authentication and authorization mechanisms.