CVE-2025-30384 is a high-severity vulnerability classified under CWE-502, which involves the deserialization of untrusted data within Microsoft SharePoint Enterprise Server 2016 (version 16.0.0). Deserialization vulnerabilities occur when an application processes serialized data from untrusted sources without sufficient validation or sanitization, allowing attackers to manipulate the input to execute arbitrary code. In this case, the vulnerability allows an unauthorized attacker to execute code locally on the affected SharePoint server. The CVSS 3.1 base score of 7.4 reflects a high impact, with the vector indicating local attack vector (AV:L), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability does not require authentication or user interaction, but the attacker must have local access to the system, which could be achieved through other means such as compromised credentials or lateral movement within a network. Although no known exploits are currently reported in the wild, the potential for local code execution makes this a critical concern for organizations relying on SharePoint Enterprise Server 2016. The absence of published patches at the time of disclosure increases the urgency for mitigation and monitoring. Given SharePoint's role as a collaboration and document management platform, exploitation could lead to significant data breaches, disruption of business processes, and potential lateral movement within enterprise networks.

For European organizations, the impact of CVE-2025-30384 could be substantial. SharePoint Enterprise Server 2016 is widely used across various sectors including government, finance, healthcare, and large enterprises in Europe for document management and internal collaboration. Successful exploitation could lead to unauthorized disclosure of sensitive information, modification or deletion of critical data, and disruption of availability of SharePoint services. This could compromise compliance with stringent European data protection regulations such as GDPR, leading to legal and financial penalties. Additionally, local code execution on SharePoint servers could serve as a foothold for attackers to escalate privileges and move laterally within corporate networks, potentially affecting other critical infrastructure. The high confidentiality, integrity, and availability impacts underscore the risk of operational disruption and reputational damage. Organizations with SharePoint servers accessible to multiple users or integrated with other enterprise systems are particularly at risk.

Given the lack of an official patch at the time of disclosure, European organizations should implement several specific mitigations: 1) Restrict local access to SharePoint servers strictly to trusted administrators and monitor for any unauthorized access attempts. 2) Employ application whitelisting and endpoint protection solutions to detect and block suspicious code execution on SharePoint servers. 3) Harden SharePoint configurations by disabling unnecessary features or services that could be exploited for local access or deserialization attacks. 4) Implement network segmentation to isolate SharePoint servers from less trusted network zones, limiting lateral movement opportunities. 5) Monitor logs and system behavior for anomalies indicative of exploitation attempts, such as unexpected deserialization activity or unusual process spawning. 6) Educate administrators on the risks of deserialization vulnerabilities and the importance of applying security best practices. 7) Prepare for rapid deployment of patches once Microsoft releases an official fix, including testing in controlled environments. 8) Consider deploying application-layer firewalls or runtime application self-protection (RASP) tools that can detect and block deserialization attacks in real time.