A heap‑based buffer overflow exists in the Windows SMB Client, allowing an attacker with network access to elevate privileges on the target system. The flaw arises when the client processes specially crafted SMB packets, resulting in a buffer overflow that can compromise the privileged context of the process

Microsoft Windows 10 versions 1607, 1809, 21H2 and 22H2; Microsoft Windows 11 versions 23H2, 24H2, 25H2, 26H2 and 26H1; Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022 and 2025, including core installations, are all affected because they include the vulnerable SMB client stack

The CVSS score of 8.8 indicates a high severity vulnerability. The EPSS score is not available, so the likelihood of exploitation is uncertain, but the vulnerability is not listed in the CISA KEV catalog. Attackers can exploit this flaw by sending malicious SMB traffic from the network, which could lead to privilege escalation and potentially compromise the entire system.