An out‑of‑bounds read within the Windows Sysmain Service allows an authorized local user to gain elevated privileges on the affected system. The flaw does not provide arbitrary code execution but enables a local user to acquire higher‑level access rights.

Microsoft Windows 10 versions 1607, 1809, 21H2 and 22H2; Microsoft Windows 11 versions 23H2, 24H2, 25H2, 26H2 and 26H1; Microsoft Windows Server 2016 and Windows Server 2019, including Server Core installations.

The CVSS score of 7.8 reflects high severity, while the EPSS score of less than 1 percent indicates a low likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog. Local authorized access is required; an attacker with desktop or constrained user privileges can trigger the out‑of‑bounds read to elevate privileges to a higher level on the same machine.