CVE-2025-50159 is a use-after-free vulnerability categorized under CWE-416 found in the Remote Access Point-to-Point Protocol (PPP) EAP-TLS component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). Use-after-free vulnerabilities occur when a program continues to use memory after it has been freed, leading to undefined behavior such as memory corruption, crashes, or execution of arbitrary code. In this case, the flaw allows an authorized attacker with local access to exploit the vulnerability to elevate privileges on the affected system. The attacker must have limited privileges and requires user interaction to trigger the flaw, but once exploited, they can gain higher privileges potentially up to SYSTEM level. The vulnerability affects confidentiality, integrity, and availability of the system by enabling unauthorized access and control. The CVSS v3.1 base score is 7.3 (high), reflecting the local attack vector, low attack complexity, required privileges, and user interaction. No public exploits or active exploitation have been reported yet. The vulnerability was reserved in June 2025 and published in August 2025. No patches are currently linked, indicating that organizations should monitor for updates from Microsoft. The vulnerability specifically impacts Windows 10 Version 1809, an older but still in-use version of Windows 10, often found in legacy systems or environments with strict update policies. The PPP EAP-TLS protocol is commonly used for secure remote access, meaning environments relying on this protocol for VPN or dial-up connections are particularly vulnerable.

For European organizations, this vulnerability poses a significant risk especially in sectors where legacy Windows 10 1809 systems remain operational, such as manufacturing, healthcare, and government institutions with strict change control. The ability for a local attacker to elevate privileges can lead to full system compromise, data breaches, and disruption of critical services. Confidentiality is at risk as attackers could access sensitive data; integrity is compromised through potential unauthorized changes; and availability may be affected by system crashes or denial of service. Organizations using PPP EAP-TLS for remote access are particularly exposed, as attackers could leverage this protocol to gain initial foothold or escalate privileges. The lack of known exploits in the wild provides a window for proactive mitigation, but the high severity score indicates that once exploited, the consequences could be severe. European entities with remote workforce setups or legacy VPN infrastructures should be especially vigilant. The vulnerability also raises compliance concerns under GDPR if personal data is exposed due to exploitation.

1. Monitor Microsoft security advisories closely and apply official patches immediately upon release to address CVE-2025-50159. 2. Until patches are available, restrict local access to systems running Windows 10 Version 1809, especially those exposed to untrusted users. 3. Disable or restrict the use of PPP EAP-TLS for remote access where possible, or replace it with more secure and updated VPN protocols. 4. Implement strict user privilege management to minimize the number of users with local access and limit privileges to the minimum necessary. 5. Employ endpoint detection and response (EDR) solutions to monitor for suspicious activities related to privilege escalation attempts. 6. Conduct regular audits of legacy systems and plan for upgrades to supported Windows versions to reduce exposure to unpatched vulnerabilities. 7. Educate users about the risks of interacting with untrusted applications or prompts that could trigger the vulnerability. 8. Use application whitelisting and exploit mitigation technologies such as Control Flow Guard (CFG) and Data Execution Prevention (DEP) to reduce exploitation likelihood.