CVE-2025-50159 is a high-severity use-after-free vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0), specifically within the Remote Access Point-to-Point Protocol (PPP) implementation of the Extensible Authentication Protocol-Transport Layer Security (EAP-TLS). The vulnerability arises due to improper handling of memory, where a previously freed object is accessed, leading to undefined behavior. This flaw can be exploited by an authorized local attacker to elevate privileges on the affected system. The attacker must have local access and some level of privileges (low privileges) and must interact with the system (user interaction required) to trigger the vulnerability. Successful exploitation could allow the attacker to execute arbitrary code with elevated privileges, compromising confidentiality, integrity, and availability of the system. The CVSS v3.1 base score is 7.3, reflecting high severity, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), privileges required (PR:L), user interaction (UI:R), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that mitigation may rely on workarounds or vendor updates in the near future. The vulnerability is categorized under CWE-416 (Use After Free), a common memory corruption issue that can lead to arbitrary code execution or system crashes.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and government agencies still operating legacy Windows 10 Version 1809 systems. The ability for a local attacker to elevate privileges can lead to full system compromise, enabling lateral movement, data exfiltration, or deployment of ransomware. Organizations with remote access infrastructure relying on PPP EAP-TLS for authentication are particularly vulnerable if attackers gain local access through social engineering, phishing, or insider threats. The high impact on confidentiality, integrity, and availability means sensitive data and critical systems could be compromised, disrupting business operations and causing regulatory compliance issues under GDPR. Since Windows 10 Version 1809 is an older release, some organizations may not have upgraded, increasing their exposure. The lack of known exploits in the wild currently reduces immediate risk but also means attackers may develop exploits once patches are released or reverse-engineered.

1. Immediate mitigation should include restricting local access to systems running Windows 10 Version 1809, enforcing strict access controls and monitoring for suspicious activity. 2. Disable or restrict use of PPP EAP-TLS authentication where possible, or transition to more secure authentication protocols. 3. Apply principle of least privilege to limit user rights, reducing the impact of any local exploit. 4. Monitor for unusual behavior or privilege escalation attempts using endpoint detection and response (EDR) tools. 5. Prepare for patch deployment by inventorying affected systems and testing updates once Microsoft releases a security patch. 6. Consider upgrading affected systems to a supported Windows version with ongoing security updates to eliminate exposure. 7. Educate users about the risks of local privilege escalation and enforce policies to prevent unauthorized software installation or execution. 8. Employ application whitelisting to prevent exploitation of memory corruption vulnerabilities.