Heap-based buffer overflow in FreeRDP - CVE-2026-121962
Published: November 10, 2026 / Updated: November 11, 2026
Vulnerability identifier: #VU164443
CSH Severity: High
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-121962
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to corrupt client heap memory or cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in FreeRDP's transport_default_read_pdu when processing partial Early User Authorization reads using total capacity instead of remaining space. A remote attacker can operate an RDP server that completes PROTOCOL_HYBRID_EX CredSSP with a connecting client and repeatedly send incomplete four-byte results to overwrite heap memory in assert-free builds or abort assertion-enabled clients.
Affected software
FreeRDP
How to mitigate CVE-2026-121962
Install security update from vendor's website.
FreeRDP - update to 3.32.2