Out-of-bounds write in FreeRDP - #VU146591
Published: September 1, 2026
Vulnerability identifier: #VU146591
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause memory corruption.
The vulnerability exists due to an out-of-bounds write in ntlm_computeMicValue in winpr/libwinpr/sspi/NTLM/ntlm.c when processing an NTLM AUTHENTICATE message. A remote attacker can send a specially crafted NTLM AUTHENTICATE message to cause memory corruption.
Exploitation requires a server that has registered the SspiNtlmHashCallback API callback, and no shipped FreeRDP binary enables this path.
Affected software
FreeRDP
Remediation
Install security update from vendor's website.
FreeRDP - update to 3.31.0