CVE-2025-55694 is an improper access control vulnerability classified under CWE-284, discovered in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The vulnerability resides in the Windows Error Reporting component, which is responsible for collecting and reporting error data to Microsoft. Due to flawed access control mechanisms, an authorized local attacker—someone with limited privileges on the system—can exploit this vulnerability to elevate their privileges to a higher level, potentially SYSTEM or administrator level. This elevation of privilege does not require user interaction, increasing the risk of automated or stealthy exploitation. The vulnerability impacts confidentiality, integrity, and availability by allowing attackers to bypass security restrictions and gain unauthorized control over the system. The CVSS v3.1 base score is 7.8, indicating a high severity with local attack vector, low attack complexity, and requiring privileges but no user interaction. No public exploits or active exploitation 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 necessitates immediate attention to mitigation strategies to reduce exposure. This vulnerability is particularly critical in environments where Windows 11 25H2 is deployed and where local user accounts have limited privileges but could be leveraged for privilege escalation.

For European organizations, this vulnerability poses a significant risk, especially in sectors relying heavily on Windows 11 25H2, such as finance, healthcare, government, and critical infrastructure. Successful exploitation could allow attackers to gain elevated privileges, leading to unauthorized access to sensitive data, disruption of services, or deployment of further malware such as ransomware. The ability to escalate privileges locally means that insider threats or attackers who have gained initial footholds via other means can leverage this flaw to deepen their control over systems. This could result in data breaches, operational downtime, and compliance violations under regulations like GDPR. The absence of known exploits currently reduces immediate risk but does not diminish the potential impact once exploit code becomes available. Organizations with large Windows 11 deployments and complex user environments are at higher risk due to the increased attack surface.

Organizations should prioritize the following mitigations: 1) Monitor Microsoft security advisories closely and apply official patches immediately upon release to remediate the vulnerability. 2) Restrict local user privileges to the minimum necessary to reduce the pool of accounts that can exploit this flaw. 3) Implement application whitelisting and endpoint detection and response (EDR) solutions to detect abnormal privilege escalation attempts. 4) Harden Windows Error Reporting settings where possible, including disabling or limiting error reporting in sensitive environments until patches are applied. 5) Conduct regular audits of local accounts and privilege assignments to identify and remediate excessive permissions. 6) Employ network segmentation to limit lateral movement if privilege escalation occurs. 7) Educate IT staff and users about the risks of local privilege escalation and encourage reporting of suspicious activity. These steps go beyond generic advice by focusing on minimizing the attack surface and increasing detection capabilities while awaiting patches.