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

High 8.7 Published 1 Aug 2026 Updated 3 Aug 2026

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

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

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

Which versions are affected by CVE-2026-67299?

It affects 1 product.

Products include Freerdp Freerdp.

How do I fix CVE-2026-67299?

Upgrade to a fixed version.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-67299 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67299 exists.

All Freerdp Freerdp vulnerabilities

Sources

Also known as CLSA-2026-1787750352, DEBIAN-CVE-2026-67299, GHSA-34hq-hwjw-q8v3, GHSA-jq8c-588g-4wgj, UBUNTU-CVE-2026-67299.