CVE-2025-30382 is a high-severity vulnerability identified in Microsoft SharePoint Enterprise Server 2016, specifically version 16.0.0. The vulnerability is categorized under CWE-502, which pertains to the deserialization of untrusted data. Deserialization vulnerabilities occur when an application deserializes data from untrusted sources without sufficient validation, allowing attackers to manipulate serialized objects to execute arbitrary code. In this case, the flaw allows an unauthorized attacker to execute code locally on the affected SharePoint server by exploiting the deserialization process. The CVSS 3.1 base score of 7.8 reflects a high severity, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact is critical across confidentiality, integrity, and availability, as successful exploitation can lead to full system compromise. Although no known exploits are currently reported in the wild, the vulnerability's nature and impact make it a significant risk. The lack of available patches at the time of publication increases the urgency for mitigations and monitoring. Given SharePoint's role as a collaboration and document management platform, exploitation could lead to unauthorized access to sensitive organizational data and disruption of business operations.

For European organizations, this vulnerability poses a substantial risk due to the widespread use of Microsoft SharePoint Enterprise Server 2016 in enterprise environments for document management, collaboration, and intranet services. Exploitation could lead to unauthorized code execution on critical servers, potentially resulting in data breaches involving personal data protected under GDPR, intellectual property theft, and disruption of business continuity. The local attack vector and requirement for user interaction mean that insider threats or social engineering could facilitate exploitation. The high impact on confidentiality, integrity, and availability could lead to regulatory penalties, reputational damage, and financial losses. Additionally, given the interconnected nature of European enterprises and supply chains, a compromised SharePoint server could serve as a pivot point for lateral movement within networks, amplifying the threat.

European organizations should implement the following specific mitigations: 1) Immediately audit and monitor SharePoint Enterprise Server 2016 instances for unusual activity indicative of exploitation attempts, focusing on local user actions and deserialization processes. 2) Restrict local access to SharePoint servers to trusted personnel only, enforcing strict access controls and multi-factor authentication to reduce the risk of unauthorized local interactions. 3) Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and prevent unauthorized code execution on SharePoint servers. 4) Disable or limit features in SharePoint that involve deserialization of user-supplied data where possible, or apply configuration hardening to reduce attack surface. 5) Maintain up-to-date backups and develop incident response plans specifically addressing deserialization attacks. 6) Engage with Microsoft support channels to obtain any available patches or workarounds as soon as they are released and prioritize their deployment. 7) Conduct user awareness training to reduce the risk of social engineering that could facilitate exploitation requiring user interaction.