CVE-2025-29838 is a high-severity vulnerability identified in Microsoft Windows Server 2025, specifically affecting the Server Core installation variant. The vulnerability is classified as a NULL Pointer Dereference (CWE-476) within Windows Drivers. This flaw allows an unauthorized local attacker to cause a NULL pointer dereference, which can lead to a system crash or unexpected behavior. More critically, this vulnerability can be exploited to elevate privileges locally, granting the attacker higher-level access rights than originally permitted. The vulnerability affects version 10.0.26100.0 of Windows Server 2025 Server Core. The CVSS v3.1 score of 7.4 reflects a high severity rating, indicating significant impact on confidentiality, integrity, and availability. The attack vector is local (AV:L), requiring the attacker to have local access to the system but no privileges (PR:N) or user interaction (UI:N) is needed. The attack complexity is high (AC:H), meaning exploitation requires specific conditions or expertise. The vulnerability impacts confidentiality, integrity, and availability (all rated high), which means successful exploitation could lead to full system compromise. No known exploits are currently in the wild, and no patches have been published yet. The vulnerability was reserved in March 2025 and published in May 2025. The Server Core installation is a minimalistic Windows Server deployment option commonly used in enterprise environments to reduce attack surface and resource usage, but this vulnerability undermines that security posture by allowing privilege escalation through a driver-level flaw.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and data centers relying on Windows Server 2025 Server Core installations for critical infrastructure, cloud services, and internal applications. Successful exploitation could allow attackers with local access—such as malicious insiders, compromised user accounts, or attackers who gain physical or remote access through other means—to escalate privileges and gain administrative control. This could lead to unauthorized data access, disruption of services, deployment of ransomware or other malware, and lateral movement within networks. Given the high confidentiality, integrity, and availability impact, organizations could face data breaches, operational downtime, and regulatory compliance violations under GDPR. The lack of a patch at the time of disclosure increases the urgency for mitigation. The Server Core's typical use in high-security environments means this vulnerability could undermine trust in these deployments and potentially expose sensitive government, financial, healthcare, and industrial control systems prevalent in Europe.

1. Immediate mitigation should focus on restricting local access to Windows Server 2025 Server Core systems. Implement strict access controls, including limiting physical and remote console access to trusted administrators only. 2. Employ robust endpoint detection and response (EDR) solutions to monitor for suspicious local privilege escalation attempts or abnormal driver behavior. 3. Use application whitelisting and driver signing enforcement to prevent unauthorized or malicious drivers from loading. 4. Harden the server environment by disabling unnecessary services and interfaces that could be leveraged to gain local access. 5. Regularly audit user accounts and permissions to minimize the number of users with local access and administrative privileges. 6. Until an official patch is released, consider deploying virtualized or containerized environments to isolate critical workloads and reduce the attack surface. 7. Stay informed through Microsoft security advisories and apply patches immediately once available. 8. Conduct penetration testing and vulnerability assessments focusing on local privilege escalation vectors to identify potential exploitation paths within the environment.