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CVE-2026-73291

HIGHCVSS 7.1/10EPSS 0.27%

Last modified

CVE-2026-73291 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Prior to version 3.4.0, Seerr's ImageProxy in server/lib/imageproxy.ts uses the upstream ETag and Content-Type response headers to build a cache filename for the unauthenticated GET /avatarproxy/:jellyfinUserId route, allowing a malicious or compromised Jellyfin or Emby server, or a man-in-the-middle attacker on a plaintext media-server connection, to supply traversal sequences that path.join and fs.writeFile normalize outside the cache directory, overwrite /app/dist/index.js or other files, and execute code as the node user after a container restart. EPSS estimates a 0.27% chance of exploitation in the next 30 days.

Description

Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Prior to version 3.4.0, Seerr's ImageProxy in server/lib/imageproxy.ts uses the upstream ETag and Content-Type response headers to build a cache filename for the unauthenticated GET /avatarproxy/:jellyfinUserId route, allowing a malicious or compromised Jellyfin or Emby server, or a man-in-the-middle attacker on a plaintext media-server connection, to supply traversal sequences that path.join and fs.writeFile normalize outside the cache directory, overwrite /app/dist/index.js or other files, and execute code as the node user after a container restart. This issue is fixed in version 3.4.0.

Metrics

CVSS 3.1
7.1/10

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:H

EPSS Probability
0.27%

19.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
seerr-teamseerr< 3.4.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-73291?
Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Prior to version 3.4.0, Seerr's ImageProxy in server/lib/imageproxy.ts uses the upstream ETag and Content-Type response headers to build a cache filename for the unauthenticated GET /avatarproxy/:jellyfinUserId route, allowing a malicious or compromised Jellyfin or Emby server, or a man-in-the-middle attacker on a plaintext media-server connection, to supply traversal sequences that path.join and fs.writeFile normalize outside the cache directory, overwrite /app/dist/index.js or other files, and execute code as the node user after a container restart. This issue is fixed in version 3.4.0.
How severe is CVE-2026-73291?
CVE-2026-73291 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.
How do I fix CVE-2026-73291?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST