Executive brief
A security vulnerability exists in a core Windows networking component responsible for managing socket connections. An attacker who already has basic access to a computer could exploit this flaw to gain higher-level system privileges. This could allow them to bypass certain security restrictions or cause a system crash, impacting the stability and security of the workstation or server.
Technical details
A use-after-free (UAF) vulnerability (CWE-416) exists within the Windows Ancillary Function Driver (afd.sys), which serves as the entry point for the Windows Sockets (WinSock) interface. The flaw is triggered when the driver improperly manages memory objects during socket operations, allowing an attacker to reuse memory that has already been freed. To exploit this, an attacker must have local access and the ability to execute code with low privileges. While the CVSS score emphasizes a high complexity (AC:H) and impact on availability, UAF vulnerabilities in this component are traditionally leveraged for local privilege escalation (LPE) to SYSTEM. Microsoft has released security updates to address this issue across multiple versions of Windows and Windows Server.
Affected products
- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 24H2, 25H2, 26H1
- Microsoft Windows Server 2012 All versions
Timeline
- 2026-07-14: disclosed
- 2026-07-14: advisory