# CVE-2026-35031: Jellyfin: Potential RCE via subtitle upload path traversal + .strm chain

> Attackers with subtitle upload permissions can exploit path traversal to write arbitrary files, leading to remote code execution and privilege escalation.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Apr 2026
- **Updated:** 16 Apr 2026
- **Also known as:** GHSA-j2hf-x4q5-47j3

## What is CVE-2026-35031?

CVE-2026-35031 is a critical path traversal vulnerability in jellyfin, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-20 (Improper Input Validation), CWE-187 (Partial String Comparison)

## Which versions are affected by CVE-2026-35031?

It affects 1 product.


Products: Jellyfin Jellyfin.

## How do I fix CVE-2026-35031?

No fix has been published for CVE-2026-35031 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-35031 being exploited?

There is no known exploitation of CVE-2026-35031 in the wild and no public exploit code.

Public exploit code:

- Critical path traversal to RCE vulnerability in Jellyfin Media Server (CVSS 9.9). Includes proof-of-concept exploit, technical analysis, and detection tools. (github_poc): https://github.com/keraattin/CVE-2026-35031

## Other vulnerabilities in jellyfin

- [CVE-2026-31852](https://insights.sbomify.com/CVE-2026-31852/): Jellyfin Possible Organization/Secret Compromise from dangerous CI implementation (critical 10.0)
- [CVE-2026-35033](https://insights.sbomify.com/CVE-2026-35033/): Jellyfin: Potential SSRF + Arbitrary file read via stream argument injection (critical 9.3)
- [CVE-2023-30627](https://insights.sbomify.com/CVE-2023-30627/): jellyfin-web has a stored cross-site scripting vulnerability in devices.js (critical 9.1)
- [CVE-2023-30626](https://insights.sbomify.com/CVE-2023-30626/): Jellyfin vulnerable to directory traversal and file write causing arbitrary code execution (high 8.8)
- [CVE-2022-35909](https://insights.sbomify.com/CVE-2022-35909/): Incorrect Access Control and Cross Site Scripting in Jellyfin (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35031 and fix it if it is affected.

What it is: CVE-2026-35031 is a critical path traversal vulnerability in jellyfin, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-35031 in the wild and no public exploit code.

Affected product: jellyfin. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-35031/ (Markdown: https://insights.sbomify.com/CVE-2026-35031/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35031
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35031
- OSV: https://osv.dev/vulnerability/CVE-2026-35031

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35031/
Summaries are generated and may contain mistakes; the official description above is the record.