FreeRDP up to 3.30.x WinPR Stream_EnsureRemainingCapacity integer overflow

Summaryinfo

A vulnerability marked as problematic has been reported in FreeRDP up to 3.30.x. This impacts the function Stream_EnsureRemainingCapacity of the component WinPR. The manipulation leads to integer overflow. This vulnerability is listed as CVE-2026-91960. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in FreeRDP up to 3.30.x and classified as problematic. This issue affects the function Stream_EnsureRemainingCapacity of the component WinPR. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is availability. The summary by CVE is:

FreeRDP versions before 3.31.0 contain an integer overflow in WinPR's Stream_EnsureRemainingCapacity function that allows remote attackers to cause denial of service. A malicious RD Gateway peer can send a WebSocket Ping frame with a crafted 64-bit extended payload length to trigger integer wraparound, resulting in a double free that crashes the FreeRDP client during connection.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-91960 since 09/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

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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