CVE-2025-54111 is a use-after-free vulnerability classified under CWE-416, affecting the Windows UI XAML Phone DatePickerFlyout component in Microsoft Windows 10 Version 1809 (build 17763.0). This vulnerability arises when the system improperly handles memory management, specifically freeing memory that is still in use, which can be exploited by an authorized local attacker to execute arbitrary code with elevated privileges. The attacker must have limited privileges on the system but does not require user interaction to exploit the flaw. The vulnerability impacts the confidentiality, integrity, and availability of the system by allowing privilege escalation, potentially enabling attackers to gain SYSTEM-level access. The CVSS v3.1 score of 7.8 reflects a high severity, with attack vector local (AV:L), attack complexity high (AC:H), privileges required low (PR:L), no user interaction (UI:N), and scope changed (S:C). The vulnerability was reserved in July 2025 and published in September 2025, with no known exploits in the wild at the time of publication. No official patches have been linked yet, indicating that affected organizations should monitor vendor advisories closely. The vulnerability is particularly relevant for environments still running Windows 10 Version 1809, which is an older, out-of-support version for many organizations but may still be in use in legacy systems. Exploitation could lead to full system compromise, making it critical to address in sensitive environments.

For European organizations, the impact of CVE-2025-54111 is significant, especially for those relying on legacy Windows 10 Version 1809 systems. Successful exploitation allows attackers to escalate privileges locally, potentially leading to full system compromise, unauthorized data access, and disruption of critical services. This is particularly concerning for sectors such as government, finance, healthcare, and critical infrastructure, where confidentiality and integrity of data are paramount. The vulnerability could be leveraged by insider threats or attackers who have gained limited access through other means to deepen their foothold. Given the high severity and scope change, the vulnerability could facilitate lateral movement within networks, increasing the risk of widespread compromise. The lack of user interaction requirement further raises the threat level in controlled environments. European organizations with strict compliance requirements (e.g., GDPR) could face regulatory and reputational consequences if exploited. The absence of known exploits currently provides a window for proactive mitigation but also underscores the urgency to patch or upgrade systems before exploitation attempts emerge.

1. Apply official patches or security updates from Microsoft as soon as they become available for Windows 10 Version 1809. 2. If patches are not yet available, consider upgrading affected systems to a supported and fully patched Windows version to eliminate exposure. 3. Restrict local access to systems running Windows 10 Version 1809 by enforcing strict access controls and limiting administrative privileges to reduce the risk of exploitation. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities indicative of privilege escalation attempts. 5. Conduct regular system audits to identify and remediate legacy systems still running vulnerable versions. 6. Educate IT staff about the vulnerability and ensure incident response plans include scenarios involving local privilege escalation. 7. Use virtualization or sandboxing techniques for legacy applications that require Windows 10 Version 1809 to isolate potential exploitation impact. 8. Monitor threat intelligence feeds for emerging exploit code or active campaigns targeting this vulnerability to enable rapid response.