CVE-2026-25176 is a vulnerability classified under CWE-284 (Improper Access Control) affecting the Windows Ancillary Function Driver for WinSock in Microsoft Windows 10 Version 1607 (build 10.0.14393.0). The flaw allows an authorized attacker with local access to elevate privileges on the affected system. The vulnerability arises due to improper enforcement of access controls within the WinSock driver, which is responsible for network socket operations. An attacker who already has some level of access can exploit this flaw to gain higher privileges, potentially SYSTEM-level, thereby compromising the confidentiality, integrity, and availability of the system. The CVSS v3.1 base score is 7.8, reflecting high severity, with attack vector Local (AV:L), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), and unchanged scope (S:U). The impact metrics indicate high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits have been reported in the wild as of the publication date. The vulnerability was reserved on January 29, 2026, and published on March 10, 2026. No official patches or mitigation links are currently available, indicating that organizations must rely on interim controls until a patch is released. This vulnerability is particularly concerning for environments where Windows 10 Version 1607 remains in use, often in legacy or embedded systems.

The vulnerability allows local attackers to escalate privileges, potentially gaining SYSTEM-level access, which can lead to full control over affected systems. This can result in unauthorized access to sensitive data, installation of persistent malware, disruption of services, and lateral movement within networks. Organizations relying on Windows 10 Version 1607, especially those with legacy systems that cannot be easily upgraded, face significant risk. Critical infrastructure, government agencies, and enterprises with strict compliance requirements could suffer severe operational and reputational damage if exploited. The lack of user interaction requirement and low attack complexity increase the likelihood of exploitation once a local foothold is established. Although no exploits are currently known in the wild, the high severity and potential impact necessitate proactive measures.

1. Prioritize upgrading or migrating systems from Windows 10 Version 1607 to a supported, updated Windows version where this vulnerability is patched. 2. Until patches are available, restrict local access to trusted users only and enforce the principle of least privilege to minimize the number of users with local access. 3. Implement enhanced monitoring and logging of local privilege escalation attempts and anomalous activities related to WinSock driver usage. 4. Use application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious behavior indicative of privilege escalation. 5. Harden systems by disabling unnecessary services and network features that could be leveraged in conjunction with this vulnerability. 6. Conduct regular security audits and vulnerability assessments focusing on legacy systems to identify and remediate similar risks. 7. Educate IT staff and users about the risks of local privilege escalation and the importance of maintaining updated systems.