CVE-2024-26195 is a high-severity heap-based buffer overflow vulnerability (CWE-122) affecting the DHCP Server service in Microsoft Windows Server 2019, specifically version 10.0.17763.0. This vulnerability allows remote code execution (RCE) due to improper handling of DHCP packets, where an attacker can send specially crafted DHCP requests to the vulnerable server. The flaw resides in the DHCP Server service's processing logic, which fails to properly validate or limit the size of input data, leading to a heap buffer overflow. Exploiting this vulnerability could enable an attacker with network access to the DHCP server to execute arbitrary code with elevated privileges, potentially taking full control of the affected system. The CVSS v3.1 base score is 7.2, indicating a high severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), but requiring high privileges (PR:H) and no user interaction (UI:N). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No known exploits are currently reported in the wild, and no official patches or mitigation links have been published yet. The vulnerability was reserved in February 2024 and published in April 2024, indicating recent discovery and disclosure. Given the critical role of DHCP in network infrastructure, exploitation could disrupt network services and compromise server integrity in enterprise environments running Windows Server 2019 DHCP services.

For European organizations, this vulnerability poses a significant risk to critical IT infrastructure, especially in sectors relying heavily on Windows Server 2019 for DHCP services, such as telecommunications, finance, government, and large enterprises. Successful exploitation could lead to remote code execution, allowing attackers to gain control over DHCP servers, manipulate network configurations, disrupt IP address allocation, and potentially pivot to other internal systems. This could result in widespread network outages, data breaches, and loss of service availability. Given that DHCP servers often operate in perimeter or internal network segments, an attacker exploiting this flaw could bypass network segmentation and escalate privileges. The requirement for high privileges to exploit may limit some attack scenarios but does not eliminate risk, especially in environments with weak internal access controls or compromised credentials. The absence of known exploits in the wild currently reduces immediate threat but does not preclude rapid weaponization. The impact on confidentiality, integrity, and availability is high, making this a critical concern for maintaining operational continuity and data security in European organizations.

1. Immediate deployment of any available security updates or patches from Microsoft once released is critical. Monitor official Microsoft security advisories for patch availability. 2. Restrict network access to DHCP servers by implementing strict firewall rules and network segmentation, limiting DHCP traffic to trusted management and client subnets only. 3. Employ network intrusion detection and prevention systems (IDS/IPS) with updated signatures to detect anomalous DHCP traffic patterns indicative of exploitation attempts. 4. Enforce the principle of least privilege on accounts managing DHCP servers to reduce the risk of privilege escalation. 5. Regularly audit and monitor DHCP server logs for unusual activity or malformed DHCP requests. 6. Consider deploying DHCP failover or redundancy mechanisms to maintain service availability in case of compromise or disruption. 7. Use endpoint protection solutions capable of detecting heap-based buffer overflow exploitation techniques. 8. Conduct internal penetration testing and vulnerability assessments focusing on DHCP services to identify exposure and validate mitigations. 9. Prepare incident response plans specifically addressing DHCP server compromise scenarios to enable rapid containment and recovery.