CVE-2025-54111 is a use-after-free vulnerability classified under CWE-416, found in the Windows UI XAML Phone DatePickerFlyout component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability occurs when the system improperly manages memory, freeing an object but continuing to use its reference, which can lead to arbitrary code execution or privilege escalation. An authorized attacker with limited privileges on the local system can exploit this flaw to elevate their privileges to higher levels, potentially gaining SYSTEM-level access. The vulnerability does not require user interaction but does require local access and has a high attack complexity due to the need for specific conditions to trigger the use-after-free. The CVSS v3.1 score of 7.8 reflects its high impact on confidentiality, integrity, and availability, with a scope change indicating that the vulnerability can affect resources beyond the initially compromised component. No public exploits have been reported yet, but the vulnerability is publicly disclosed and should be treated with urgency. The lack of available patches at the time of disclosure means organizations must rely on interim mitigations and plan upgrades or patches as soon as they become available. The vulnerability affects legacy Windows 10 1809 systems, which remain in use in some enterprise environments due to compatibility or support constraints.

For European organizations, this vulnerability poses a significant risk, especially for those still operating Windows 10 Version 1809 in critical environments such as government agencies, healthcare, finance, and industrial control systems. Successful exploitation can lead to unauthorized privilege escalation, allowing attackers to bypass security controls, access sensitive data, install persistent malware, or disrupt system availability. Given the local access requirement, insider threats or attackers who have already compromised lower-privileged accounts could leverage this vulnerability to deepen their foothold. The potential for scope change means that the attack could impact multiple system components or services, increasing the risk of widespread compromise. The absence of known exploits reduces immediate risk but also means defenders must proactively address the vulnerability before attackers develop reliable exploit code. The impact is amplified in environments where legacy systems are interconnected with critical infrastructure or where patching is delayed due to operational constraints.

1. Prioritize upgrading affected systems from Windows 10 Version 1809 to a supported and patched Windows version to eliminate the vulnerability. 2. If upgrading is not immediately feasible, implement strict access controls to limit local user accounts and reduce the number of users with local login privileges. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor for suspicious behaviors indicative of privilege escalation attempts. 4. Regularly audit and restrict the use of legacy systems, especially those exposed to untrusted users or networks. 5. Apply any available interim security updates or workarounds provided by Microsoft as soon as they are released. 6. Educate system administrators and users about the risks of local privilege escalation and enforce the principle of least privilege. 7. Monitor system logs for anomalies related to the DatePickerFlyout component or unexpected process behaviors. 8. Segment networks to isolate legacy systems from critical infrastructure to reduce lateral movement opportunities.