FreeRDP up to 3.25.x CB_CLIP_CAPS PDU capabilitySetLength heap-based overflow

Summaryinfo

A vulnerability has been found in FreeRDP up to 3.25.x and classified as critical. Affected is an unknown function of the component CB_CLIP_CAPS PDU Handler. Performing a manipulation of the argument capabilitySetLength results in heap-based overflow. This vulnerability is reported as CVE-2026-44420. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in FreeRDP up to 3.25.x. It has been classified as critical. This affects an unknown part of the component CB_CLIP_CAPS PDU Handler. The manipulation of the argument capabilitySetLength with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP client can trigger a heap-buffer-overflow write in FreeRDP's server-side clipboard (cliprdr) channel by sending a CB_CLIP_CAPS PDU with a too-small capabilitySetLength. This can crash the server process (remote DoS) and may be exploitable for code execution because it corrupts heap memory. This vulnerability is fixed in 3.26.0.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-44420 since 05/06/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 318027 (Linux Distros Unpatched Vulnerability : CVE-2026-44420), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.26.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (318027) and EUVD (EUVD-2026-33435). 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

License

• open-source

Website

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

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

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