Seerr: Path traversal to RCE via /avatarproxy image cache filename from upstream ETag (CVE-2026-73291) | HOL Guard CVE

High · CVSS 7.1CVE-2026-73291

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

Answer in brief

CVE-2026-73291 records a High severity (CVSS 7.1) vulnerability in Seerr: Path traversal to RCE via /avatarproxy image cache filename from upstream ETag. The current sources do not mark it as known exploited. The current feed maps seerr-team/seerr (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 12, 2026Updated Sep 18, 2026Source checked Sep 27, 2026First seen by HOL Aug 12, 2026Material review Sep 18, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps seerr-team/seerr (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
seerr-team/seerrgeneric	<3.4.0	3.4.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for seerr-team/seerr.
Review the reported fix. Update seerr-team/seerr to 3.4.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 12, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.