Vulnerability in Jellyfin (CVE-2026-35033)
Summary
Vulnerability in Jellyfin (CVE-2026-35033). Confidential information can be exposed externally.
Original description
The description as published by the source.
Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain an unauthenticated arbitrary file read vulnerability via ffmpeg argument injection through the StreamOptions query parameter parsing mechanism. The ParseStreamOptions method in StreamingHelpers.cs adds any lowercase query parameter to a dictionary without validation, bypassing the RegularExpression attribute on the level controller parameter, and the unsanitized value is concatenated directly into the ffmpeg command line. By injecting a drawtext filter with a textfile argument, an attacker can read arbitrary server files such as /etc/shadow and exfiltrate their contents as text rendered in the video stream response. The vulnerable /Videos/{itemId}/stream endpoint has no Authorize attribute, making this exploitable without authentication, though item GUIDs are pseudorandom and require an authenticated user to obtain. This issue has been fixed in version 10.11.7.
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-2026-35033 has been found in Jellyfin.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Jellyfin CVE-2026-35033" on the vendor's site.
CVE-2026-35033 (Jellyfin) — CWE-88 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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.
A vulnerability (CWE-88) exists in Jellyfin.
Check the vendor advisory for the affected versions of Jellyfin.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
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 request patterns matching this CVE's known IOCs. Run grep -r 'Jellyfin' . 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 'Jellyfin' . | 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
Jellyfinを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF 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
- web github.com