CVE-2025-53718 in Windows
Summary
by MITRE • 08/12/2025
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 • 11/22/2025
The vulnerability identified as CVE-2025-53718 represents a critical use-after-free flaw within the Windows Ancillary Function Driver for WinSock component, which operates as part of the Windows operating system's network stack. This particular driver serves as a foundational element for socket-based network communications and is integral to various networking functionalities across Windows environments. The flaw manifests when the driver fails to properly validate memory management operations, creating a scenario where freed memory locations can be accessed or reused by subsequent operations, leading to potential arbitrary code execution. The vulnerability specifically affects systems where the Ancillary Function Driver for WinSock is actively utilized, which encompasses a broad range of Windows versions including desktop and server operating systems.
The technical implementation of this use-after-free vulnerability stems from improper handling of memory allocation and deallocation sequences within the WinSock driver subsystem. When legitimate network operations occur that involve the ancillary function driver, the system allocates memory structures to handle socket operations, but fails to adequately verify that these structures remain valid throughout the operation lifecycle. An attacker who has local authenticated access to a Windows system can exploit this condition by crafting specific network operations that trigger the driver to access freed memory regions, potentially allowing for memory corruption that could be leveraged to execute malicious code with elevated privileges. This particular flaw is classified under CWE-416, which specifically addresses the use of freed memory condition, and aligns with ATT&CK technique T1068, which focuses on local privilege escalation through kernel exploits. The vulnerability demonstrates a classic memory safety issue where the driver does not properly enforce memory boundaries during concurrent access scenarios.
The operational impact of CVE-2025-53718 extends beyond simple privilege escalation as it represents a critical attack vector for malicious actors seeking to gain unauthorized access to Windows systems. Local attackers who can authenticate to a target system can exploit this vulnerability to execute code at the kernel level, effectively bypassing standard user-mode security controls and gaining full system control. The implications are particularly severe in enterprise environments where privileged accounts may be present or where attackers can leverage initial access to escalate privileges and establish persistent footholds. This vulnerability creates opportunities for attackers to manipulate system processes, access sensitive data, and potentially move laterally within network environments. The exploitation requires local access but does not necessitate complex network conditions, making it particularly dangerous as it can be leveraged by attackers who have already compromised a system through other means. The vulnerability's impact is further amplified by the fact that the affected driver is a core component of Windows networking, meaning that any system running Windows is potentially at risk.
Mitigation strategies for CVE-2025-53718 should prioritize immediate patch deployment through Microsoft's security updates, as the vendor has released patches specifically addressing the use-after-free condition in the Ancillary Function Driver for WinSock. System administrators should implement the latest security updates and ensure that all Windows systems are properly maintained with current security patches. Additionally, organizations should consider implementing enhanced monitoring for suspicious network activities and memory access patterns that could indicate exploitation attempts. The principle of least privilege should be enforced to limit the potential impact of successful exploitation, ensuring that local accounts have minimal system privileges. Network segmentation and access controls should be reviewed to reduce the attack surface, while endpoint detection and response solutions should be configured to detect anomalous behaviors that might indicate exploitation attempts. Organizations should also consider implementing application whitelisting policies to prevent unauthorized code execution, particularly in environments where the vulnerability might be exploited to gain kernel-level access. The vulnerability highlights the importance of maintaining up-to-date security practices and proper memory management in kernel-mode drivers, as these components form the foundation of system security and are critical targets for attackers seeking to escalate privileges.