CVE-2025-55692 is a vulnerability classified under CWE-20 (Improper Input Validation) affecting Microsoft Windows 11 Version 25H2, specifically build 10.0.26200.0. The flaw resides in the Windows Error Reporting component, which fails to properly validate input data. This improper validation can be exploited by an attacker who already has authorized local access to the system to escalate their privileges. The attacker does not require user interaction to exploit this vulnerability, and the attack complexity is low, meaning that a skilled attacker with local access could reliably execute privilege escalation. The vulnerability impacts confidentiality, integrity, and availability, as elevated privileges could allow an attacker to access sensitive data, modify system configurations, or disrupt system operations. Although no public exploits are currently known, the vulnerability is rated with a CVSS 3.1 score of 7.8, indicating a high severity level. The vulnerability was reserved in August 2025 and published in October 2025, with no patches currently linked, suggesting that organizations should monitor for updates from Microsoft. The vulnerability’s scope is limited to Windows 11 Version 25H2, but given the widespread adoption of this OS version, the potential impact is significant. The flaw requires local privileges to exploit, so initial access vectors such as phishing or physical access could precede exploitation. This vulnerability underscores the importance of robust input validation in system components that handle error reporting and diagnostics.

For European organizations, this vulnerability poses a significant risk, especially in environments where Windows 11 Version 25H2 is deployed extensively. Successful exploitation could lead to unauthorized privilege escalation, enabling attackers to bypass security controls, access sensitive corporate data, and potentially disrupt critical business operations. Sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the sensitive nature of their data and the potential for operational disruption. The lack of required user interaction increases the risk of automated or stealthy attacks once local access is obtained. Additionally, the vulnerability could be leveraged as a stepping stone for lateral movement within networks, increasing the scope of compromise. The absence of known exploits in the wild currently reduces immediate risk, but the high severity and ease of exploitation mean that threat actors may develop exploits rapidly. European organizations with remote or hybrid work environments should be cautious, as local access could be gained through compromised endpoints. Overall, the vulnerability could undermine trust in Windows 11 systems and necessitate urgent security reviews and patch management.

1. Restrict local access to Windows 11 Version 25H2 systems by enforcing strict access controls and using multi-factor authentication for local logins where possible. 2. Monitor and audit Windows Error Reporting processes and logs for unusual activity that could indicate exploitation attempts. 3. Apply the principle of least privilege rigorously, ensuring users and services operate with minimal necessary permissions to limit the impact of privilege escalation. 4. Implement endpoint detection and response (EDR) solutions capable of detecting anomalous privilege escalation behaviors. 5. Isolate critical systems and segment networks to reduce the risk of lateral movement following exploitation. 6. Stay informed about Microsoft’s security advisories and apply patches promptly once released. 7. Conduct regular vulnerability assessments and penetration testing focused on privilege escalation vectors. 8. Educate IT staff and users about the risks of local access compromise and enforce policies to prevent unauthorized physical or remote access. 9. Consider temporary workarounds such as disabling Windows Error Reporting if feasible and safe within the operational context until patches are available. 10. Maintain robust backup and recovery procedures to mitigate potential damage from exploitation.