# CVE-2026-125240: FFmpeg through 9.0.2 Resource Leak in libsvtjpegxs JPEG XS Decoder Wrapper


- **Severity:** Medium 6.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 9 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-gjhm-46vw-wmhg, UBUNTU-CVE-2026-125240

## What is CVE-2026-125240?

CVE-2026-125240 is a medium-severity vulnerability in FFmpeg, published on 9 Nov 2026. 

### Official description

FFmpeg through 9.0.2 contains a resource leak vulnerability in svt_jpegxs_dec_decode() in libsvtjpegxsdec.c that leaks decoder instances when ff_set_dimensions() rejects frame dimensions. Attackers can supply a crafted JPEG XS stream, for example in MPEG-TS, with oversized headers to repeatedly leak decoder threads and buffers, exhausting memory.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-125240?


## How do I fix CVE-2026-125240?

No fix has been published for CVE-2026-125240 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-125240 being exploited?

There is no known exploitation of CVE-2026-125240 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125240 and fix it if it is affected.

What it is: CVE-2026-125240 is a medium-severity vulnerability in FFmpeg, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-125240 in the wild and no public exploit code.

Affected product: FFmpeg. 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-2026-125240/ (Markdown: https://insights.sbomify.com/CVE-2026-125240/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125240
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125240
- OSV: https://osv.dev/vulnerability/CVE-2026-125240

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125240/
Summaries are generated and may contain mistakes; the official description above is the record.