CVE-2025-53805 is an out-of-bounds read vulnerability classified under CWE-125, affecting Microsoft Windows Server 2022 specifically in the Windows Internet Information Services (IIS) component. This vulnerability arises from improper bounds checking in IIS, allowing an attacker to read memory outside the intended buffer boundaries. While this does not lead to information disclosure or code execution, it can cause the IIS process or the entire server to crash, resulting in a denial of service (DoS). The vulnerability is remotely exploitable over the network without requiring any authentication or user interaction, increasing its risk profile. The CVSS v3.1 base score is 7.5, reflecting high severity due to the ease of exploitation and impact on availability. The affected version is 10.0.20348.0 of Windows Server 2022. There are no known exploits in the wild at the time of publication, and no patches have been released yet. The vulnerability was reserved in July 2025 and published in September 2025, indicating recent discovery. IIS is widely used for hosting web applications and services, making this vulnerability a significant concern for organizations relying on Windows Server 2022 for critical web infrastructure. Attackers could leverage this flaw to disrupt services, potentially impacting business continuity and availability of online resources.

For European organizations, the primary impact of CVE-2025-53805 is the potential denial of service on critical web services hosted on Windows Server 2022 IIS. This can disrupt business operations, customer-facing applications, and internal services dependent on IIS. Sectors such as finance, healthcare, government, and telecommunications, which often rely on Microsoft server products, could experience significant operational downtime. The lack of confidentiality or integrity compromise limits data breach risks but does not diminish the operational impact. Disruption of services could also affect compliance with regulatory requirements around service availability and incident response. Given the ease of exploitation without authentication or user interaction, attackers could launch automated attacks causing widespread outages. The absence of known exploits currently provides a window for proactive mitigation, but the high severity score necessitates urgent attention to prevent potential future exploitation. Organizations with internet-facing IIS servers are particularly vulnerable, and the impact could extend to supply chains and critical infrastructure reliant on these services.

1. Immediately restrict network exposure of IIS servers by implementing strict firewall rules to limit access to trusted IP addresses and internal networks. 2. Employ network-level intrusion detection and prevention systems (IDS/IPS) to monitor and block suspicious traffic targeting IIS. 3. Disable or limit unnecessary IIS modules and features to reduce the attack surface. 4. Monitor IIS server logs and system event logs for unusual crashes or service interruptions indicative of exploitation attempts. 5. Apply any available Microsoft security updates promptly once released; subscribe to Microsoft security advisories for real-time updates. 6. Consider deploying web application firewalls (WAF) with custom rules to detect and block malformed requests that could trigger the vulnerability. 7. Implement robust server hardening practices, including least privilege configurations and regular vulnerability scanning. 8. Prepare incident response plans specifically for IIS service disruptions to minimize downtime and recovery time. 9. For critical environments, evaluate temporary migration or load balancing to unaffected servers or platforms until patches are available. 10. Educate IT staff about this vulnerability and ensure rapid communication channels for patch deployment and incident management.