CVE-2025-21311

CVE-2025-21311 is a Windows NTLM V1 Elevation of Privilege Vulnerability, published on 2025-01-14. It affects the NTLM V1 authentication component in Windows systems, as indicated by the CWE-303 association and lack of additional CWE details from NVD.

The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical. Remote attackers require only network access, with low attack complexity, no privileges, and no user interaction. Exploitation enables elevation of privilege, resulting in high impacts to confidentiality, integrity, and availability.

Microsoft's Security Response Center provides vulnerability update guidance, including patches and mitigations, at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21311.