What’s Vulnerable › Vulnerabilities

CVE-2026-67300: FreeRDP before 3.29.0 Use-After-Free via async message proxy

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-01 · updated 2026-08-31
• Weakness: CWE-416

Description

FreeRDP before 3.29.0 contains client-side heap use-after-free vulnerabilities in the async update message proxy for RAIL WINDOW_STATE_ORDER and NOTIFY_ICON_STATE_ORDER when AsyncUpdate is enabled. When a malicious or compromised RDP server sends crafted update orders, the message proxy shallow-copies structures containing nested parser-owned pointers (e.g., titleInfo.string, windowRects, visibilityRects, icon buffers). The parser frees those nested buffers after the callback returns, so the queued async message later dispatches stale pointers, potentially causing memory corruption or a client crash.

Affected products

• FreeRDP: before 3.29.0 — fixed in 3.29.0

How to fix

Upgrade to a fixed version: FreeRDP 3.29.0. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/commit/5370fb26fbf034ecd11d3026b6ad639b5fff493f
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-33gg-h66j-3697
• https://www.vulncheck.com/advisories/freerdp-before-use-after-free-via-async-message-proxy

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