Reachable assertion in FreeRDP - CVE-2026-91961
Published: September 1, 2026 / Updated: September 16, 2026
Vulnerability identifier: #VU146596
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-91961
CWE-ID: CWE-617
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to reachable assertion in URBDRC/libusb control-transfer path when processing a server-supplied URBDRC control-transfer request. A remote attacker can send a crafted request with an oversized OutputBufferSize value to cause a denial of service.
The issue is triggered when OutputBufferSize is set to 65536, and exploitation affects builds that use the URBDRC libusb path after the user connects to a malicious server.
Affected software
FreeRDP
How to mitigate CVE-2026-91961
Install security update from vendor's website.
FreeRDP - update to 3.31.0