# CVE-2026-67301: FreeRDP before 3.29.0 Out-of-bounds Read via Polygon async message-proxy

> A malicious RDP server can trigger an out-of-bounds read in FreeRDP clients, leading to memory disclosure or crashes when async updates are enabled.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** CLSA-2026-1789779158, CLSA-2026-1789779650, DEBIAN-CVE-2026-67301, GHSA-vpv4-cm44-pgmc, GHSA-vxp3-7g6q-rq2w, UBUNTU-CVE-2026-67301

## What is CVE-2026-67301?

CVE-2026-67301 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeRDP before 3.29.0 contains out-of-bounds read vulnerabilities in the async update message proxy for the PolygonSC and PolygonCB primary drawing orders. When AsyncUpdate is enabled (e.g., xfreerdp /async-update), update_message_PolygonSC() and update_message_PolygonCB() allocate a fresh points array but copy point data from the address of the order structure instead of from polygonSC->points / polygonCB->points, resulting in a client-side out-of-bounds read. A malicious or compromised RDP server sending crafted PolygonSC/PolygonCB update orders can trigger memory disclosure or a client crash.

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

## Which versions are affected by CVE-2026-67301?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-67301?

Upgrade to a fixed version.

## Is CVE-2026-67301 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67301 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-2026-67301 and fix it if it is affected.

What it is: CVE-2026-67301 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67301 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-2026-67301/ (Markdown: https://insights.sbomify.com/CVE-2026-67301/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67301
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67301
- OSV: https://osv.dev/vulnerability/CVE-2026-67301

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67301/
Summaries are generated and may contain mistakes; the official description above is the record.