CVE-2026-25179 is a vulnerability identified in Microsoft Windows 10 Version 1607 (build 10.0.14393.0) affecting the Windows Ancillary Function Driver for WinSock. The root cause is improper validation of the specified type of input, categorized under CWE-1287, which relates to insufficient validation of input types leading to security issues. This flaw allows an attacker who already has some level of local access with low privileges to exploit the vulnerability to elevate their privileges on the system. The vulnerability does not require user interaction but does require the attacker to have local access and the ability to execute code with limited privileges. The CVSS v3.1 score is 7.0 (high), reflecting the significant impact on confidentiality, integrity, and availability if exploited. The attack complexity is high, and privileges required are low, with no known exploits in the wild at the time of publication. The vulnerability is particularly concerning because privilege escalation can enable attackers to bypass security controls, install persistent malware, or access sensitive data. The affected Windows 10 version 1607 is an older release, which may still be in use in legacy environments or specialized systems. No patch links are provided in the data, indicating that organizations should verify with Microsoft for updates or consider upgrading to newer Windows versions that have addressed this issue.

The primary impact of CVE-2026-25179 is local privilege escalation, which can allow an attacker with limited access to gain higher privileges, potentially SYSTEM-level access. This can lead to full system compromise, enabling the attacker to install malware, access or modify sensitive data, disable security controls, and disrupt system availability. Organizations with legacy Windows 10 Version 1607 systems, especially in critical infrastructure sectors such as government, finance, healthcare, and industrial control systems, face increased risk of targeted attacks leveraging this vulnerability. The exploitation complexity is high, reducing the likelihood of widespread automated attacks, but targeted attacks by skilled adversaries remain a concern. The lack of known exploits in the wild suggests limited current exploitation, but the vulnerability's existence in an older, possibly unsupported OS version increases risk over time as attackers develop techniques. Overall, this vulnerability threatens confidentiality, integrity, and availability of affected systems, potentially leading to significant operational and reputational damage.

1. Apply official security patches from Microsoft as soon as they become available for Windows 10 Version 1607. If no patch is currently available, monitor Microsoft security advisories closely. 2. Upgrade affected systems to a supported and fully patched version of Windows 10 or later to eliminate exposure to this vulnerability. 3. Restrict local access to systems running Windows 10 Version 1607 by enforcing strict access controls, limiting user accounts with local login rights, and using network segmentation to reduce attack surface. 4. Implement application whitelisting and endpoint protection solutions that can detect and block suspicious privilege escalation attempts. 5. Monitor system logs and security events for unusual local privilege escalation activities, including unexpected process creations or modifications to system files and registry keys. 6. Conduct regular vulnerability assessments and penetration testing focusing on legacy systems to identify and remediate similar issues proactively. 7. Educate IT staff and users about the risks of running unsupported OS versions and the importance of timely patching and system upgrades.