---
cve: "CVE-2026-35031"
severity: "CRITICAL"
cvss: 10.0
epss: "0.8%"
vendor: "jellyfin"
kev: false
exploited: false
published: "2026-04-14 23:16:28"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-11-10T01:56:03+01:00"
---

# CVE-2026-35031

> 10.0 CRITICAL · 🧪 PoC

## Beschreibung

Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain a vulnerability chain in the subtitle upload endpoint (POST /Videos/{itemId}/Subtitles), where the Format field is not validated, allowing path traversal via the file extension and enabling arbitrary file write. This arbitrary file write can be chained into arbitrary file read via .strm files, database extraction, admin privilege escalation, and ultimately remote code execution as root via ld.so.preload. Exploitation requires an administrator account or a user that has been explicitly granted the "Upload Subtitles" permission. This issue has been fixed in version 10.11.7. If users are unable to upgrade immediately, they can grant non-administrator users Subtitle upload permissions to reduce attack surface.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-04-16 13:56:06
- CNA-CVSS: **10.0** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-187** — Partial String Comparison
  The product performs a string comparison that only examines a portion of the string before determining whether there is a match.
- **CWE-20** — Improper Input Validation
  The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- **CWE-22** — Improper Limitation of a Pathname to a Restricted Directory
  The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

## Patch verfügbar (OSV)

- b2aa80ce5c1af2a4478d13b50c0961e11a6f5e6b (Commit)
- 29a6a0fd50862615f8e88fefbeee35957a5ed051 (Commit)

## Referenzen

- <https://github.com/jellyfin/jellyfin/security/advisories/GHSA-j2hf-x4q5-47j3>
- <https://github.com/jellyfin/jellyfin/releases/tag/v10.11.7>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-35031/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_