CVE-2026-85791

CVE-2026-85791 is a heap-based buffer overflow vulnerability identified in the Windows Encrypting File System (EFS) component of Microsoft Windows. Disclosed during Microsoft's October 2026 Patch Tuesday, the flaw affects multiple versions of Windows, including Windows 10 and Windows Server. The vulnerability stems from a coding deficiency within the EFS component, which can be targeted by attackers. To exploit this vulnerability, an authorized local attacker with low privileges must execute a specially crafted application on the target system. Because the attack vector is local and requires high attack complexity, it does not require user interaction. Successful exploitation allows the attacker to elevate their privileges locally, potentially gaining higher-level access or full system control. Microsoft has released official security updates to address and patch this vulnerability.