# CVE-2026-49246: Jellyfin: Potential MKV attachment filename path traversal to RCE

> Attackers can achieve remote code execution on Jellyfin media servers by uploading crafted MKV files with malicious attachment filenames.

- **Severity:** Low 1.7 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** GHSA-f47c-m7gr-q92j

## What is CVE-2026-49246?

CVE-2026-49246 is a low-severity path traversal vulnerability in jellyfin, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Jellyfin is an open source self hosted media server. Prior to 10.11.10, a specifically crafted MKV file containing forged filename tags can be leveraged to exploit missing path sanitization during playback. Jellyfin treats the MKV file name tag on MKV attachments as trusted and passes it unsanitized into Path.Combine(attachmentFolder, fileName) inside PathManager.GetAttachmentPath. Because .NET's Path.Combine neither normalises .. nor rejects a rooted second argument, a crafted MKV can redirect Jellyfin's MKV attachment extraction to any absolute path on disk. This triggers on any playback action of the affected video on a client which will attempt to burn in the subtitles by default.g This vulnerability is fixed in 10.11.10.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-49246?


## How do I fix CVE-2026-49246?

No fix has been published for CVE-2026-49246 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-49246 being exploited?

There is no known exploitation of CVE-2026-49246 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49246 and fix it if it is affected.

What it is: CVE-2026-49246 is a low-severity path traversal vulnerability in jellyfin, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-49246 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-2026-49246/ (Markdown: https://insights.sbomify.com/CVE-2026-49246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49246
- OSV: https://osv.dev/vulnerability/CVE-2026-49246

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49246/
Summaries are generated and may contain mistakes; the official description above is the record.