Path Traversal in Seerr (CVE-2026-73291)
Summary
Path traversal in Seerr (CVE-2026-73291). Data can be tampered with by attackers. Exploitable via GET /avatarproxy/.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-73291 has been found in Seerr.
Attackers can target a specific entry point like GET /avatarproxy/ over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Seerr CVE-2026-73291" on the vendor's site.
CVE-2026-73291 (Seerr) — CWE-22 / CVSS v3 7.1
Attack vector: adjacent-network / unauthenticated / no user interaction
Attack surface: GET /avatarproxy/
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in Seerr. Attackers reach the vulnerable code path via GET /avatarproxy/ without authentication.
Check the vendor advisory for the affected versions of Seerr. Attack surface: GET /avatarproxy/.
Severity: High (CVSS 7.1/10). Data can be tampered with by attackers.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /avatarproxy/ requests with malformed payloads or SQL meta-characters. Run grep -r 'Seerr' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Seerr' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Seerrを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /avatarproxy/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /avatarproxy/への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against GET /avatarproxy/ on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- web github.com