Out-of-bounds write in FreeRDP - CVE-2026-121954
Published: November 10, 2026 / Updated: November 11, 2026
Vulnerability identifier: #VU164430
CSH Severity: Medium
CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-121954
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to corrupt client heap memory and cause a denial of service.
The vulnerability exists due to non-atomic geometry and buffer updates in FreeRDP's planar codec when ResetGraphics buffer allocation fails under constrained address space, leaving new dimensions paired with undersized buffers and NULL pointers. A remote attacker can operate an RDP server, complete the handshake, and send ResetGraphics with width=height=32766 followed by a PLANAR command containing YCoCg with non-zero cll or BGRA32 RAW with an NA header to trigger out-of-bounds or NULL-pointer writes.
Affected software
FreeRDP
How to mitigate CVE-2026-121954
Install security update from vendor's website.
FreeRDP - update to 3.32.2