CVE-2025-53805 is an out-of-bounds read vulnerability classified under CWE-125 affecting Microsoft Windows Server 2022, specifically the Internet Information Services (IIS) component. The vulnerability arises from IIS improperly handling certain network requests, leading to an out-of-bounds memory read. This flaw can be triggered remotely by an unauthenticated attacker without any user interaction, allowing them to cause a denial of service by crashing the IIS service or the entire server. The CVSS v3.1 score of 7.5 reflects a high severity due to the network attack vector, low attack complexity, and no required privileges or user interaction. Although this vulnerability does not compromise data confidentiality or integrity, the impact on availability can disrupt critical web services hosted on Windows Server 2022. No public exploits have been reported yet, but the vulnerability’s characteristics make it a candidate for exploitation once weaponized. The lack of an available patch at the time of publication necessitates immediate risk mitigation through network controls and monitoring. This vulnerability highlights the importance of securing IIS deployments and maintaining up-to-date server software in enterprise environments.

For European organizations, the primary impact is service disruption due to denial of service attacks targeting IIS on Windows Server 2022. This can affect public-facing websites, internal web applications, and critical infrastructure services relying on IIS, leading to operational downtime and potential loss of business continuity. Sectors such as finance, healthcare, government, and telecommunications, which heavily depend on Microsoft server technologies, could face significant availability challenges. Disruptions could also undermine trust in digital services and cause cascading effects in interconnected systems. The vulnerability’s remote exploitation capability increases the risk of widespread attacks, especially if automated exploit tools emerge. Organizations with insufficient network segmentation or exposure of IIS servers directly to the internet are particularly vulnerable. The absence of confidentiality or integrity impact limits data breach risks but does not diminish the operational threat posed by service outages.

Until an official patch is released by Microsoft, European organizations should implement the following mitigations: 1) Restrict external access to IIS servers by using firewalls and network segmentation to limit exposure only to trusted networks or VPNs. 2) Employ intrusion detection and prevention systems (IDS/IPS) with updated signatures to detect anomalous IIS traffic patterns indicative of exploitation attempts. 3) Monitor IIS logs and system event logs for unusual crashes or memory access errors that could signal exploitation attempts. 4) Consider temporarily disabling non-essential IIS features or services that increase the attack surface. 5) Apply strict rate limiting and filtering on HTTP requests to IIS to mitigate potential DoS vectors. 6) Prepare for rapid deployment of official patches by maintaining robust update management processes. 7) Conduct internal vulnerability assessments and penetration testing focused on IIS to identify exposure. These targeted actions go beyond generic advice by focusing on network-level controls, monitoring, and operational readiness specific to this vulnerability.