CVE-2025-49726 is a high-severity use-after-free vulnerability (CWE-416) identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw exists within the Windows Notification component, which handles system notifications. A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, leading to undefined behavior such as memory corruption. In this case, an authorized local attacker can exploit this vulnerability to elevate privileges on the affected system. The attacker must have limited privileges (local privileges) but does not require user interaction to trigger the exploit. The vulnerability has a CVSS v3.1 base score of 7.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and requiring only low privileges. No known exploits are currently reported in the wild, and no official patches or mitigations have been published yet. However, the vulnerability is publicly disclosed and assigned a CVE identifier, indicating the need for immediate attention. Exploiting this vulnerability could allow an attacker to execute arbitrary code with elevated privileges, potentially leading to full system compromise, unauthorized access to sensitive data, and disruption of system operations. The vulnerability affects a legacy Windows 10 version (1809), which is still in use in some enterprise environments but is no longer the latest supported version, increasing the risk for organizations that have not upgraded or patched their systems.

For European organizations, this vulnerability poses a significant risk, especially for those still running Windows 10 Version 1809 in production environments. Privilege escalation vulnerabilities can be leveraged by attackers who have gained initial access through other means (e.g., phishing, malware) to gain administrative control over systems. This can lead to lateral movement within networks, data breaches, disruption of critical services, and potential compliance violations under regulations such as GDPR. Organizations in sectors with high regulatory and operational sensitivity, such as finance, healthcare, government, and critical infrastructure, are particularly at risk. The lack of known exploits in the wild currently reduces immediate threat but does not eliminate the risk, as attackers may develop exploits rapidly following public disclosure. The vulnerability’s impact on confidentiality, integrity, and availability is high, meaning successful exploitation could compromise sensitive personal and business data, alter system configurations, or cause system outages.

1. Immediate assessment of all systems running Windows 10 Version 1809 to identify vulnerable hosts. 2. Prioritize upgrading affected systems to a newer, supported Windows version where this vulnerability is not present or has been patched. 3. Until patches are available, implement strict access controls to limit local user privileges and reduce the number of users with local access rights. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor for suspicious activities indicative of privilege escalation attempts. 5. Regularly audit and monitor system logs for unusual behavior related to Windows Notification processes. 6. Educate users and administrators about the risks of privilege escalation and the importance of applying security updates promptly. 7. Follow Microsoft’s security advisories closely for the release of official patches or workarounds and apply them immediately upon availability. 8. Consider network segmentation to isolate vulnerable systems and limit potential lateral movement by attackers.