FreeRDP up to 3.30.x URBDRC OutputBufferSize assertion

Summaryinfo

A vulnerability was found in FreeRDP up to 3.30.x. It has been classified as problematic. This impacts an unknown function of the component URBDRC. Performing a manipulation of the argument OutputBufferSize results in assertion. This vulnerability is known as CVE-2026-91961. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic has been found in FreeRDP up to 3.30.x. This affects an unknown code block of the component URBDRC. The manipulation of the argument OutputBufferSize with an unknown input leads to a assertion vulnerability. CWE is classifying the issue as CWE-617. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary. This is going to have an impact on availability. The summary by CVE is:

FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer request with OutputBufferSize set to 65536, triggering a reachable assertion that terminates the client process.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-91961 since 09/15/2026. 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. Technical details are known, but no exploit is available.

Upgrading to version 3.31.0 eliminates this vulnerability.

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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
• 3.29
• 3.30

License

• open-source

Website

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

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