# CVE-2026-125249: FFmpeg 7.1 through 9.0.2 Heap Out-of-Bounds Write via Vulkan Slice Buffer Sizing


- **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/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-qjxq-q85p-hv2c, UBUNTU-CVE-2026-125249

## What is CVE-2026-125249?

CVE-2026-125249 is a high-severity vulnerability in FFmpeg, published on 9 Nov 2026. 

### Official description

FFmpeg 7.1 through 9.0.2 contains an integer overflow in ff_vk_decode_add_slice() in libavcodec/vulkan_decode.c that miscalculates the Vulkan hwaccel bitstream buffer size. Attackers can supply a crafted stream with over 2 GiB of slice data per frame, causing memcpy() to write past a smaller pooled host-mapped buffer.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-125249?


## How do I fix CVE-2026-125249?

No fix has been published for CVE-2026-125249 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-125249 being exploited?

There is no known exploitation of CVE-2026-125249 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125249 and fix it if it is affected.

What it is: CVE-2026-125249 is a high-severity vulnerability in FFmpeg, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-125249 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-2026-125249/ (Markdown: https://insights.sbomify.com/CVE-2026-125249/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125249
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125249
- OSV: https://osv.dev/vulnerability/CVE-2026-125249

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125249/
Summaries are generated and may contain mistakes; the official description above is the record.