CVE-2024-26183 is a vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting build 10.0.17763.0. The issue is classified as a NULL Pointer Dereference (CWE-476) within the Windows Kerberos authentication component. This vulnerability can be triggered remotely without user interaction and requires low privileges (PR:L), meaning an attacker with some level of authenticated access could exploit it. The flaw causes a denial of service (DoS) condition by crashing the affected system or service due to improper handling of NULL pointers during Kerberos operations. Kerberos is a critical authentication protocol used widely in enterprise environments for secure identity verification and ticket granting. Exploiting this vulnerability does not compromise confidentiality or integrity but results in the loss of availability of the authentication service or potentially the entire system, disrupting normal operations. The CVSS v3.1 base score is 6.5 (medium severity), with attack vector network (AV:N), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), and scope unchanged (S:U). No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that mitigation may rely on workarounds or configuration changes until an official update is released. The vulnerability was publicly disclosed in April 2024 and has been enriched by CISA for awareness and tracking. Given the nature of the flaw, it primarily impacts systems still running the older Windows 10 1809 version, which is past mainstream support but may still be in use in some environments.

For European organizations, the impact of CVE-2024-26183 can be significant in environments where Windows 10 Version 1809 remains deployed, particularly in legacy systems or specialized infrastructure that has not been upgraded. The denial of service caused by this vulnerability could disrupt authentication services, leading to potential downtime of critical business applications relying on Kerberos authentication. This could affect enterprise networks, government agencies, and critical infrastructure sectors such as finance, healthcare, and manufacturing, where Windows 10 1809 might still be operational. Although the vulnerability does not allow data theft or system takeover, the loss of availability in authentication services can halt user access, delay operations, and increase helpdesk workload. In highly regulated sectors, such interruptions could also lead to compliance issues. The medium severity rating reflects the moderate risk, but the ease of exploitation (network accessible, no user interaction) means attackers could leverage this flaw to cause targeted disruptions, especially in environments with limited patch management or legacy system dependencies.

Prioritize upgrading affected systems from Windows 10 Version 1809 to a supported and patched version of Windows 10 or Windows 11 to eliminate exposure to this vulnerability. Implement network segmentation to isolate legacy systems running Windows 10 1809 from critical infrastructure and limit exposure to untrusted networks. Restrict access to Kerberos services by applying strict firewall rules and limiting network access to only trusted hosts and administrative users. Monitor network traffic for unusual Kerberos authentication requests or repeated connection attempts that could indicate exploitation attempts. Apply any available Microsoft security updates or advisories as soon as they are released, and subscribe to vendor notifications for timely patch deployment. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect anomalous Kerberos traffic patterns related to NULL pointer dereference attempts. Establish incident response procedures specifically for authentication service disruptions to quickly restore service availability and minimize operational impact.