Executive brief
Windows Update Stack, a core component responsible for installing security patches and system updates on Windows computers, contains a flaw that allows attackers with local access to gain system-level permissions. An attacker exploiting this vulnerability could take full control of a Windows machine, compromising all data and operations on that system. This vulnerability is already being actively exploited by attackers in the wild.
Technical details
The vulnerability is a link following (arbitrary file access or symbolic link traversal) issue within the Windows Update Stack component. It allows a local, authenticated attacker to escalate privileges to SYSTEM level without requiring administrative rights. The attack vector is local, meaning the attacker must have access to the target system. The root cause relates to improper handling of file paths or symbolic links during Update Stack operations. An attacker can exploit this to execute arbitrary code with SYSTEM privileges, gaining complete control of the affected Windows system. Active exploitation in the wild indicates this is a high-priority patch.
Affected products
- Microsoft Windows Update Stack
Timeline
- 2026-09-08: disclosed
- exploited