Reachable assertion in FreeRDP - CVE-2026-121406
Published: November 10, 2026 / Updated: November 11, 2026
Vulnerability identifier: #VU164437
CSH Severity: Low
CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-121406
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 by aborting FreeRDP clients with assertions enabled.
The vulnerability exists due to a reachable assertion in rdpgfx_on_data_received when successful zero-output ZGFX decompression leaves a null pointer that is passed to Stream_StaticConstInit without validation. A remote attacker can entice a victim to connect to a malicious RDP server and send E0 20 00 over RDPGFX after session activation to abort the client; the empty multipart payload E1 00 00 00 00 00 00 also triggers the assertion in component testing.
Affected software
FreeRDP
How to mitigate CVE-2026-121406
Install security update from vendor's website.
FreeRDP - update to 3.32.2