CVE-2025-29971 is a high-severity vulnerability identified in Microsoft Windows 11 version 22H2, specifically affecting build 10.0.22621.0. The flaw is an out-of-bounds read (CWE-125) in the Web Threat Defense driver (WTD.sys), a component responsible for network-level threat inspection and mitigation. An out-of-bounds read occurs when a program reads data past the boundary of allocated memory, potentially leading to system instability or crashes. In this case, the vulnerability allows an unauthorized attacker to trigger a denial-of-service (DoS) condition remotely over the network without requiring any authentication or user interaction. The CVSS v3.1 base score is 7.5, indicating a high severity level, with attack vector being network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact is limited to availability (A:H), with no confidentiality or integrity impact. The scope remains unchanged (S:U). Although no known exploits are currently reported in the wild, the vulnerability's nature and ease of exploitation make it a significant risk for affected systems. The absence of a patch link suggests that remediation may still be pending or in progress. This vulnerability could be exploited by sending specially crafted network packets to the vulnerable system, causing the WTD.sys driver to perform an out-of-bounds read, leading to system crashes or reboots, thereby disrupting normal operations and potentially affecting network security monitoring capabilities.

For European organizations, the impact of CVE-2025-29971 can be substantial, especially for enterprises relying on Windows 11 version 22H2 in critical infrastructure, corporate networks, or cloud environments. The vulnerability enables remote denial-of-service attacks without authentication, which could be leveraged by threat actors to disrupt business continuity, degrade network security monitoring, or cause downtime in essential services. Sectors such as finance, healthcare, government, and telecommunications, which often deploy Windows 11 in their environments, may face operational interruptions and increased risk exposure. Additionally, the disruption of Web Threat Defense could reduce the effectiveness of network threat detection, potentially opening a window for secondary attacks. Given the network-based attack vector and lack of required privileges, attackers can exploit this vulnerability from remote locations, increasing the risk of widespread impact across interconnected systems. The absence of known exploits currently provides a limited window for mitigation before active exploitation might emerge.

Organizations should prioritize the following specific mitigation steps: 1) Monitor official Microsoft security advisories closely for the release of a patch addressing CVE-2025-29971 and apply it immediately upon availability. 2) Implement network-level protections such as intrusion detection/prevention systems (IDS/IPS) to detect and block anomalous traffic patterns targeting the WTD.sys component. 3) Restrict exposure of Windows 11 22H2 systems running Web Threat Defense to untrusted networks by using firewalls and network segmentation to limit attack surface. 4) Employ network traffic filtering to block or rate-limit suspicious packets that could trigger the out-of-bounds read condition. 5) Maintain up-to-date backups and incident response plans to quickly recover from potential denial-of-service incidents. 6) Conduct internal vulnerability scans and penetration tests focusing on network drivers and related components to identify any exploitation attempts. 7) Educate IT and security teams about the vulnerability specifics to enhance monitoring and rapid response capabilities. These targeted actions go beyond generic advice by focusing on network exposure reduction, proactive detection, and readiness for incident recovery.