CVE-2025-49726 is a high-severity use-after-free vulnerability (CWE-416) affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw exists within the Windows Notification component, where improper handling of memory leads to a use-after-free condition. This vulnerability allows an authorized local attacker to elevate privileges on the affected system without requiring user interaction. Specifically, the attacker must have some level of local access (low privileges) and can exploit this flaw to execute arbitrary code or manipulate system processes with elevated privileges, potentially gaining administrative control. The CVSS v3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no user interaction needed. Although no known exploits are currently reported in the wild, the vulnerability’s nature and impact make it a significant risk for affected systems. No official patches or mitigation links have been published yet, indicating that organizations must monitor for updates and consider interim mitigations. The vulnerability’s exploitation scope is local, requiring an attacker to have some access to the system, but once exploited, it can lead to full system compromise due to privilege escalation.

For European organizations, this vulnerability poses a substantial risk, especially in environments where Windows 10 Version 1809 remains in use, such as legacy systems or specialized industrial setups. Successful exploitation could allow attackers to bypass security controls, access sensitive data, disrupt operations, or deploy further malware with elevated privileges. This is particularly concerning for sectors with strict data protection requirements like finance, healthcare, and government, where confidentiality and integrity are paramount. The ability to elevate privileges locally could facilitate lateral movement within networks, increasing the risk of broader compromise. Additionally, organizations relying on endpoint security solutions that may not detect such exploitation could face delayed incident response. The lack of user interaction requirement increases the risk of automated or stealthy attacks once local access is gained. Given the vulnerability affects a core Windows component, the potential impact on availability and system stability is also significant, potentially leading to denial of service or system crashes.

1. Immediate mitigation should focus on minimizing local access to systems running Windows 10 Version 1809 by enforcing strict access controls, including limiting administrative privileges and using application whitelisting. 2. Employ endpoint detection and response (EDR) tools capable of monitoring suspicious memory operations and privilege escalation attempts. 3. Disable or restrict Windows Notification features where feasible, especially on high-risk or sensitive systems, to reduce the attack surface. 4. Implement network segmentation to isolate legacy systems and reduce the risk of lateral movement if a system is compromised. 5. Regularly audit and monitor local user accounts and privilege assignments to detect unauthorized changes. 6. Stay vigilant for official patches or security advisories from Microsoft and apply updates promptly once available. 7. Consider upgrading affected systems to a supported and patched Windows version to eliminate exposure to this vulnerability. 8. Conduct targeted penetration testing and vulnerability assessments focusing on privilege escalation vectors to identify and remediate potential exploitation paths.