CVE-2026-61348 in Windows
Summary
by MITRE • 08/11/2026
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability under discussion represents a use-after-free condition within the Windows Ancillary Function Driver for WinSock component, which serves as a critical system interface for socket operations and network communication. This flaw exists in the kernel-mode driver responsible for managing auxiliary network functions and is particularly concerning due to its potential for privilege escalation. The issue stems from improper memory management where freed memory blocks are still being accessed or referenced after deallocation, creating opportunities for exploitation.
The technical implementation of this vulnerability involves a race condition or improper handling of reference counting within the driver's memory allocation routines. When network operations occur through the WinSock API, the ancillary function driver processes these requests and manages associated memory structures. If an attacker can manipulate the timing or sequence of these operations, they may be able to cause the driver to access freed memory locations that have been reallocated for different purposes. This condition falls under the CWE-416 category of Use After Free vulnerabilities, which are classified as critical security flaws due to their potential for arbitrary code execution and privilege escalation.
From an operational perspective, this vulnerability presents a significant threat as it requires only local authentication to exploit, making it accessible to any user with valid login credentials on the target system. The attacker can leverage this condition to escalate privileges from standard user level to SYSTEM level access, effectively gaining complete control over the affected Windows system. This privilege escalation capability undermines fundamental security boundaries and allows for persistent access, data exfiltration, and further lateral movement within network environments. The attack surface is particularly broad since the ancillary function driver interfaces with numerous network applications and services.
The exploitation process typically involves creating a controlled environment where the attacker can repeatedly allocate and free memory blocks while manipulating network operations to trigger the use-after-free condition. Once successful, the attacker can inject malicious code into kernel space, bypassing standard security mechanisms such as DEP and ASLR. This vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and T1543 which addresses 'Create or Modify System Process'. The impact extends beyond individual system compromise to potentially enable broader network infiltration, as compromised systems can serve as launch points for additional attacks within enterprise environments.
Mitigation strategies include applying the latest security patches from Microsoft, which address the specific memory management issues in the affected driver components. System administrators should implement strict access controls and monitor network activity for unusual patterns that might indicate exploitation attempts. Additionally, deploying kernel-mode protection mechanisms such as Driver Signature Enforcement and Control Flow Guard can help detect and prevent exploitation attempts. Regular security assessments and vulnerability scanning should focus on identifying systems running outdated versions of the affected driver components, while implementing network segmentation to limit potential damage from successful compromises.