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TI-2026-51416 Aliases CVE-2026-73291

Seerr: Path traversal to RCE via /avatarproxy image cache filename from upstream ETag

Priority LOW 31CWE-22Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
Low · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-94.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00387 32nd percentileScored 2026-11-07
Fix Fixed seerr (seerr-team): 3.4.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
seerr-teamseerrbefore 3.4.03.4.0Patch availableCNA
  • seerr Vendorseerr-team Affected before 3.4.0 Fixed in 3.4.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:seerr:seerr:*:*:*:*:*:*:*:*——seerr-team
  • cpe:2.3:a:seerr:seerr:*:*:*:*:*:*:*:* Versions — — ·seerr-team

Remediation

  • Fix · CNA seerr (seerr-team) Fixed in 3.4.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73291

References

Other 3

  • TI-2026-22083 Plex-configured Seerr instances vulnerable to unauthenticated account registration via Jellyfin authentication endpoint CVSS 3.1CRITICAL 9.8
  • TI-2026-22147 Seerr has Broken Object-Level Authorization in User Profile Endpoint that Exposes Third-Party Notification Credentials CVSS 3.1MEDIUM 6.5
  • TI-2026-22146 Seerr missing authentication on pushSubscription endpoints CVSS 3.1MEDIUM 5.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences