Seerr
Monthly
Path traversal via unsanitized upstream ETag and Content-Type headers in Seerr's ImageProxy allows a malicious or compromised Jellyfin or Emby media server—or a network-positioned MITM attacker on a plaintext connection—to write arbitrary files outside the cache directory, overwriting critical application files such as /app/dist/index.js for deferred code execution as the Node.js process user. All Seerr releases prior to 3.4.0 are affected; the unauthenticated /avatarproxy/:jellyfinUserId endpoint is the attack surface and requires no credentials against Seerr itself. No public exploit has been identified at time of analysis, though the fix commit fully documents the vulnerable code path, making reconstruction straightforward.
Seerr prior to version 3.1.0 leaks sensitive third-party API credentials (Pushover, Pushbullet, Telegram) through the GET /api/v1/user/:id endpoint to any authenticated user regardless of privilege level. When combined with CVE-2026-27707 (unauthenticated account creation), an attacker can gain zero-prior-access to extract credentials for all users including administrators. The vulnerability is fixed in version 3.1.0.
Seerr versions 2.7.0 through 3.0.x contain an authorization bypass in push subscription API endpoints that allows authenticated users to read and modify other users' data due to missing permission checks. An attacker with valid credentials can exploit this to access sensitive information and alter configurations belonging to arbitrary accounts. The vulnerability is fixed in version 3.1.0.
Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. [CVSS 7.3 HIGH]
Path traversal via unsanitized upstream ETag and Content-Type headers in Seerr's ImageProxy allows a malicious or compromised Jellyfin or Emby media server—or a network-positioned MITM attacker on a plaintext connection—to write arbitrary files outside the cache directory, overwriting critical application files such as /app/dist/index.js for deferred code execution as the Node.js process user. All Seerr releases prior to 3.4.0 are affected; the unauthenticated /avatarproxy/:jellyfinUserId endpoint is the attack surface and requires no credentials against Seerr itself. No public exploit has been identified at time of analysis, though the fix commit fully documents the vulnerable code path, making reconstruction straightforward.
Seerr prior to version 3.1.0 leaks sensitive third-party API credentials (Pushover, Pushbullet, Telegram) through the GET /api/v1/user/:id endpoint to any authenticated user regardless of privilege level. When combined with CVE-2026-27707 (unauthenticated account creation), an attacker can gain zero-prior-access to extract credentials for all users including administrators. The vulnerability is fixed in version 3.1.0.
Seerr versions 2.7.0 through 3.0.x contain an authorization bypass in push subscription API endpoints that allows authenticated users to read and modify other users' data due to missing permission checks. An attacker with valid credentials can exploit this to access sensitive information and alter configurations belonging to arbitrary accounts. The vulnerability is fixed in version 3.1.0.
Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. [CVSS 7.3 HIGH]