Executive brief
A security vulnerability exists in the Windows component responsible for managing network socket connections. An attacker who already has basic access to a computer could exploit this flaw to gain full administrative control over the system. This could allow them to bypass security restrictions, access sensitive data, or install malicious software.
Technical details
A type confusion vulnerability (CWE-843) exists in the Windows Ancillary Function Driver (afd.sys), which is the kernel-entry point for the Winsock interface. The flaw occurs when the driver improperly handles objects of incompatible types, leading to memory corruption or unintended execution flow in kernel mode. An attacker with low-privileged local access can exploit this by sending specially crafted I/O control (IOCTL) requests to the driver. Successful exploitation allows the attacker to execute code with SYSTEM privileges. Microsoft has released security updates to address this issue across various versions of Windows and Windows Server.
Affected products
- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 22H3, 23H2, 24H2, 25H2
- Microsoft Windows Server 2008 R2 Service Pack 1
Timeline
- 2026-01-13: disclosed
- 2026-01-13: advisory