CVE-2025-29811 is a high-severity vulnerability identified in Microsoft Windows 11 version 22H2 (build 10.0.22621.0) that stems from improper input validation within the Windows Mobile Broadband component. This vulnerability is classified under CWE-20, which relates to improper input validation, and is further associated with memory safety issues such as CWE-122 (Heap-based Buffer Overflow) and CWE-125 (Out-of-bounds Read), indicating that malformed input can lead to memory corruption. The flaw allows an authorized local attacker—meaning the attacker must have some level of legitimate access to the system—to execute a privilege escalation attack. By exploiting this vulnerability, the attacker can elevate their privileges from a lower-level user context to higher privileges, potentially SYSTEM level, thereby gaining full control over the affected system. The CVSS v3.1 base score is 7.8 (high), reflecting the significant impact on confidentiality, integrity, and availability (all rated high), with low attack complexity and no user interaction required. The attack vector is local, requiring the attacker to have local access and privileges, but no additional user interaction is needed. No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that mitigation may rely on forthcoming updates from Microsoft. The vulnerability’s presence in Windows Mobile Broadband suggests that systems using cellular connectivity features on Windows 11 22H2 are at risk. Given the critical role of Windows 11 in enterprise and consumer environments, this vulnerability poses a serious risk if exploited, especially in environments where local access controls are weak or where multiple users share systems.

For European organizations, the impact of CVE-2025-29811 could be substantial. Many enterprises and public sector organizations in Europe rely heavily on Windows 11 22H2 for desktop and mobile computing, including laptops with mobile broadband capabilities for remote and field workers. Successful exploitation could allow attackers to bypass local security controls, escalate privileges, and execute arbitrary code with elevated rights. This could lead to unauthorized access to sensitive data, disruption of critical services, and potential lateral movement within corporate networks. The confidentiality, integrity, and availability of systems could be severely compromised. Particularly sensitive sectors such as finance, healthcare, government, and critical infrastructure could face increased risks of data breaches, espionage, or sabotage. The local attack vector means that insider threats or attackers who gain initial footholds through other means (e.g., phishing, physical access) could leverage this vulnerability to deepen their control. The lack of known exploits in the wild currently provides a window for organizations to prepare and patch once updates are available, but the high severity score underscores the urgency of addressing this issue promptly.

European organizations should implement a multi-layered mitigation approach: 1) Monitor for updates from Microsoft and prioritize deployment of security patches for Windows 11 version 22H2 as soon as they become available, especially for devices utilizing mobile broadband features. 2) Restrict local access to systems by enforcing strict access controls, including the use of least privilege principles and limiting administrative rights to essential personnel only. 3) Employ endpoint detection and response (EDR) solutions that can detect unusual privilege escalation attempts or anomalous behavior related to mobile broadband components. 4) Conduct regular audits of user accounts and local access logs to identify suspicious activities early. 5) For environments with mobile broadband usage, consider temporarily disabling or restricting the mobile broadband feature on Windows 11 devices if feasible until patches are applied. 6) Educate users and administrators about the risks of local privilege escalation vulnerabilities and the importance of physical and logical security controls. 7) Implement network segmentation to limit the impact of compromised devices and prevent lateral movement within the network. These targeted measures go beyond generic advice by focusing on the specific attack vector and affected component.