CVE-2025-29971 is an out-of-bounds read vulnerability classified under CWE-125, found in the Web Threat Defense driver (WTD.sys) component of Microsoft Windows 11 version 22H2 (build 10.0.22621.0). The vulnerability arises when the driver improperly handles input data, allowing an attacker to read memory beyond the intended buffer boundaries. This memory access flaw can lead to system instability or crashes, effectively causing a denial of service (DoS) condition. The vulnerability is exploitable remotely over the network without requiring any authentication or user interaction, increasing its attack surface. The CVSS v3.1 base score is 7.5, reflecting high severity due to the ease of exploitation (network vector, low attack complexity) and the impact on system availability. The vulnerability does not compromise confidentiality or integrity but can disrupt services by crashing the system or causing kernel-level faults. No patches or exploit code are currently publicly available, but the vulnerability has been officially published and tracked by Microsoft and security authorities. The Web Threat Defense driver is part of Windows security infrastructure, so its compromise can affect endpoint protection mechanisms. Organizations using Windows 11 22H2 should monitor for updates and prepare to deploy fixes promptly to prevent potential denial of service attacks.

For European organizations, the primary impact of CVE-2025-29971 is the risk of denial of service attacks that can disrupt business operations, especially for entities relying on Windows 11 22H2 endpoints in critical roles such as servers, workstations, or security appliances. The vulnerability’s network-exploitable nature means attackers can target exposed systems remotely, potentially causing widespread outages or degradation of service. This can affect availability of internal applications, remote access services, or security monitoring tools that depend on the Web Threat Defense component. Industries such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to their reliance on continuous system availability and the widespread use of Microsoft Windows platforms. Additionally, disruption of endpoint security components could increase exposure to secondary attacks. The lack of known exploits in the wild currently limits immediate risk, but the vulnerability’s characteristics warrant proactive mitigation to avoid future exploitation. The impact is heightened in environments with poor network segmentation or insufficient perimeter defenses.

To mitigate CVE-2025-29971, European organizations should: 1) Monitor Microsoft security advisories closely and apply official patches or updates for Windows 11 version 22H2 immediately upon release. 2) Implement network-level protections such as firewalls and intrusion prevention systems to restrict access to endpoints running Windows 11 from untrusted networks, minimizing exposure to remote attacks. 3) Employ network segmentation to isolate critical systems and reduce the attack surface. 4) Use endpoint detection and response (EDR) tools to monitor for unusual crashes or behavior indicative of exploitation attempts targeting WTD.sys. 5) Conduct regular vulnerability assessments and penetration testing to identify and remediate exposure. 6) Educate IT staff about the vulnerability and ensure incident response plans include scenarios for denial of service attacks affecting Windows endpoints. 7) Temporarily disable or restrict the Web Threat Defense component if feasible and if recommended by Microsoft until patches are applied. 8) Maintain up-to-date backups and recovery procedures to minimize downtime in case of successful exploitation.