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

> A local attacker with a malicious USB camera can cause a denial of service in FreeRDP via an out-of-bounds heap read.

- **Severity:** Low 2.4 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 1 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-66401, GHSA-8jj2-67pg-j6mg, GHSA-j96g-x36f-4cg4, UBUNTU-CVE-2026-66401

## What is CVE-2026-66401?

CVE-2026-66401 is a low-severity memory corruption vulnerability in Freerdp Freerdp, published on 1 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-66401?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-66401?

Upgrade to a fixed version.

## Is CVE-2026-66401 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66401 exists.

## Other vulnerabilities in Freerdp Freerdp

- [CVE-2021-37594](https://insights.sbomify.com/CVE-2021-37594/): Other in n/a (critical 9.8)
- [CVE-2021-37595](https://insights.sbomify.com/CVE-2021-37595/): Other in n/a (critical 9.8)
- [CVE-2026-67305](https://insights.sbomify.com/CVE-2026-67305/): FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr (critical 9.4)
- [CVE-2026-66402](https://insights.sbomify.com/CVE-2026-66402/): FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass (critical 9.3)
- [CVE-2026-67289](https://insights.sbomify.com/CVE-2026-67289/): FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66401 and fix it if it is affected.

What it is: CVE-2026-66401 is a low-severity memory corruption vulnerability in Freerdp Freerdp, published on 1 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66401 exists.

Affected product: Freerdp Freerdp. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-66401/ (Markdown: https://insights.sbomify.com/CVE-2026-66401/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66401
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66401
- OSV: https://osv.dev/vulnerability/CVE-2026-66401

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66401/
Summaries are generated and may contain mistakes; the official description above is the record.