FreeRDP up to 3.32.1 Shadow Server FreeRDP_WTSVirtualChannelRead denial of service

Summaryinfo

A vulnerability was found in FreeRDP. It has been declared as problematic. Affected by this issue is the function FreeRDP_WTSVirtualChannelRead of the component Shadow Server. Such manipulation leads to denial of service. This vulnerability is referenced as CVE-2026-121404. It is possible to launch the attack remotely. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in FreeRDP. Affected by this issue is the function FreeRDP_WTSVirtualChannelRead of the component Shadow Server. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. CVE summarizes:

FreeRDP before 3.32.2 contains a denial of service vulnerability in the shadow server that allows authenticated RDP clients to spin server threads by sending zero-length drdynvc DATA PDUs. Attackers can send empty DATA messages on opened audin or rdpgfx channels, so that FreeRDP_WTSVirtualChannelRead never consumes them, consuming full CPU cores until disconnect.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-121404 since 11/03/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 3.32.2 eliminates this vulnerability.

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Productinfo

Type

• Remote Access Software

Name

• FreeRDP

Version

• 1.0.0
• 1.0.1
• 1.0.2
• 1.1.0-beta+2013071101
• 1.1.0-beta1
• 2.0.0
• 2.0.0-beta1
• 2.0.0-beta1+android11
• 2.0.0-rc4
• 2.1.0
• 2.1.1
• 2.1.2
• 2.2.0
• 2.3.0
• 2.4.0
• 2.4.1
• 2.7.0
• 2.8.1
• 2.9.0
• 2.11.0
• 2.11.5
• 2.11.6
• 2.11.8
• 3.0.0
• 3.0.0-beta2
• 3.0.0-beta3
• 3.1
• 3.2.0
• 3.4
• 3.5.0
• 3.5.1
• 3.9.0
• 3.20.0
• 3.20.1
• 3.21.0
• 3.22
• 3.22.0
• 3.23.0
• 3.24.0
• 3.24.2
• 3.25.0
• 3.26.0
• 3.27
• 3.27.0
• 3.27.1
• 3.28.0
• 3.29.0
• 3.30.0
• 3.31
• 3.31.0
• 3.32.0
• 3.32.1

License

• open-source

Website

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

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CPE 2.2info

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