FreeRDP up to 3.28.x Async Update Message Proxy use after free

Summaryinfo

A vulnerability was found in FreeRDP up to 3.28.x. It has been classified as critical. This issue affects some unknown processing of the component Async Update Message Proxy. Performing a manipulation results in use after free. This vulnerability is reported as CVE-2026-67300. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in FreeRDP up to 3.28.x. This affects an unknown code block of the component Async Update Message Proxy. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-67300 since 07/29/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 331642 (Linux Distros Unpatched Vulnerability : CVE-2026-67300), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.29.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (331642) and EUVD (EUVD-2026-51821). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Remote Access Software

Name

• FreeRDP

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15
• 3.16
• 3.17
• 3.18
• 3.19
• 3.20
• 3.21
• 3.22
• 3.23
• 3.24
• 3.25
• 3.26
• 3.27
• 3.28

License

• open-source

Website

• Product: https://github.com/FreeRDP/FreeRDP/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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