CVE-2025-55681 is an out-of-bounds read vulnerability classified under CWE-125 found in the Desktop Window Manager (DWM) component of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). The flaw arises from improper bounds checking during memory operations within DWM, allowing an attacker with authorized local access and low privileges to read memory beyond allocated buffers. This memory disclosure can be leveraged to escalate privileges locally by corrupting or leaking sensitive data used by the operating system. The vulnerability does not require user interaction but does require the attacker to have some level of local access and privileges. The CVSS v3.1 score is 7.0 (high), with vector AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating local attack vector, high attack complexity, low privileges required, no user interaction, unchanged scope, and high impact on confidentiality, integrity, and availability. No public exploits have been reported yet, and no patches are currently linked, but the vulnerability is published and reserved since August 2025. The vulnerability affects Windows 11 Version 25H2 specifically, which is a recent release, meaning many organizations may have deployed this version. The flaw could be exploited by attackers to gain elevated privileges, potentially leading to full system compromise or lateral movement within networks.

For European organizations, this vulnerability poses a significant risk due to the widespread adoption of Windows 11 25H2 in enterprise and government environments. Successful exploitation could allow attackers to elevate privileges from a low-privilege user to SYSTEM or administrator level, enabling unauthorized access to sensitive data, installation of persistent malware, or disruption of critical services. This is particularly concerning for sectors such as finance, healthcare, energy, and government, where confidentiality and integrity of data are paramount. The local attack vector limits remote exploitation, but insider threats or attackers who gain initial footholds via phishing or other means could leverage this vulnerability to escalate privileges and deepen their access. The lack of known exploits currently provides a window for proactive mitigation, but the high impact on confidentiality, integrity, and availability means organizations must prioritize remediation. Additionally, the vulnerability could be used in targeted attacks against high-value European targets, increasing the risk of espionage or sabotage.

1. Monitor Microsoft security advisories closely and apply official patches immediately once released for Windows 11 Version 25H2. 2. Restrict local access to systems by enforcing strict access controls, limiting the number of users with local login rights, and using endpoint protection solutions to detect suspicious privilege escalation attempts. 3. Employ application whitelisting and least privilege principles to reduce the attack surface and prevent unauthorized code execution. 4. Conduct regular audits of user privileges and remove unnecessary local administrator rights. 5. Use advanced endpoint detection and response (EDR) tools to monitor for anomalous behavior indicative of exploitation attempts targeting DWM or privilege escalation. 6. Educate users about the risks of phishing and social engineering that could lead to initial local access. 7. Consider network segmentation to isolate critical systems and limit lateral movement opportunities if privilege escalation occurs. 8. Maintain up-to-date backups and incident response plans to quickly recover from potential compromises.