# CVE-2026-67299: FreeRDP before 3.29.0 Use-After-Free via WindowIcon async message

> A malicious RDP server can trigger a use-after-free in FreeRDP clients with async updates enabled, causing crashes or potential code execution.

- **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-2026-1787750352, DEBIAN-CVE-2026-67299, GHSA-34hq-hwjw-q8v3, GHSA-jq8c-588g-4wgj, UBUNTU-CVE-2026-67299

## What is CVE-2026-67299?

CVE-2026-67299 is a high-severity use after free 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 a client-side heap use-after-free in the async update message proxy for WINDOW_ICON_ORDER when AsyncUpdate is enabled (e.g. xfreerdp /async-update). In update_message_WindowIcon() a shallow CopyMemory() overwrites a freshly allocated lParam->iconInfo with the parser-owned windowIcon->iconInfo pointer. After the parser callback returns, update_recv_window_info_order() frees window_icon.iconInfo, but the queued async message still retains and later dispatches that stale pointer. A malicious or compromised RDP server sending a crafted RAIL Window Alternate Secondary Order with WINDOW_ORDER_ICON can trigger use-after-free, leading to memory corruption and client crash.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-67299?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-67299?

Upgrade to a fixed version.

## Is CVE-2026-67299 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67299 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-2026-67299 and fix it if it is affected.

What it is: CVE-2026-67299 is a high-severity use after free 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-2026-67299 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-2026-67299/ (Markdown: https://insights.sbomify.com/CVE-2026-67299/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67299
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67299
- OSV: https://osv.dev/vulnerability/CVE-2026-67299

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67299/
Summaries are generated and may contain mistakes; the official description above is the record.