CVE-2025-32709 in Windows
Summary
by MITRE • 05/13/2025
Null pointer dereference in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability identified as CVE-2025-32709 represents a critical null pointer dereference flaw within the Windows Ancillary Function Driver for WinSock component, which operates as a core system driver responsible for socket operations in the Windows networking stack. This driver serves as an essential interface between user-mode applications and the kernel-mode networking components, making it a prime target for privilege escalation attacks. The vulnerability specifically manifests when the driver fails to properly validate pointer references during certain socket operations, creating a scenario where a null pointer is dereferenced, leading to potential system instability and unauthorized privilege elevation.
The technical exploitation of this vulnerability occurs through local attack vectors where an authenticated user can manipulate the driver's behavior by submitting crafted socket operations that trigger the null pointer dereference condition. This flaw falls under the CWE-476 category of Null Pointer Dereference, which represents one of the most common and dangerous classes of software defects in kernel-mode drivers. The Windows Ancillary Function Driver for WinSock operates at ring 0 privilege level, meaning that successful exploitation could allow an attacker to execute arbitrary code with kernel-level privileges, effectively bypassing standard user-mode security controls and access restrictions. The attack requires local authentication since the vulnerability exists within a driver that is typically accessible only to authenticated users with standard account privileges.
From an operational impact perspective, this vulnerability presents a significant risk to enterprise environments where local user accounts may exist on systems with elevated privileges or where privilege escalation could lead to broader network compromise. The local privilege escalation capability means that an attacker who has already established a foothold on a system through other means could leverage this vulnerability to gain system-level control without requiring additional authentication or exploitation of remote attack surfaces. The exploitation process typically involves crafting specific socket operations that cause the driver to access a null pointer, potentially leading to system crashes or more dangerously, allowing code execution in kernel context. This vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation and could be used as part of a broader attack chain to establish persistent access or escalate privileges beyond initial compromise.
Mitigation strategies for CVE-2025-32709 should prioritize immediate patch deployment from Microsoft's Windows Update service, as this vulnerability requires kernel-level fixes that cannot be effectively addressed through configuration changes or workarounds. Organizations should implement comprehensive monitoring for unusual socket operations or driver behavior that might indicate exploitation attempts, particularly focusing on local user activity patterns that could suggest privilege escalation efforts. Network segmentation and least privilege principles should be enforced to limit the potential impact of successful exploitation, ensuring that even if an attacker achieves local privilege escalation, their access remains restricted to specific system components. Additionally, system administrators should conduct thorough security assessments of local user accounts and implement robust access control measures to minimize the attack surface available to potential exploiters. The vulnerability demonstrates the critical importance of maintaining up-to-date system components and the inherent risks associated with kernel-mode driver vulnerabilities that can be exploited for system-level compromise.