Program Compatibility Assistant

A newly catalogued vulnerability, EUVD-2026-73016, describes a heap-based buffer overflow in the Windows Program Compatibility Assistant affecting Microsoft Windows Server 2019, Windows 11 Version 25H2, Windows 10 Version 21H2 and more than a dozen other Windows versions. The flaw carries a CVSS v3.1 severity score of 7.0, classifying it as high severity. It was published on 8 September 2026 and updated on 7 October 2026, and security teams are being urged to check their systems for patched versions.