CVE-2025-30382 is a deserialization vulnerability classified under CWE-502 affecting Microsoft SharePoint Enterprise Server 2016 version 16.0.0. Deserialization vulnerabilities occur when untrusted data is processed by an application’s deserialization mechanism, potentially allowing attackers to manipulate the data to execute arbitrary code. In this case, the vulnerability allows an unauthorized attacker to execute code locally on the SharePoint server by exploiting the deserialization process. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) indicates that the attack requires local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:R). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). Although no public exploits are known, the vulnerability poses a serious risk because successful exploitation could lead to full system compromise, data theft, or service disruption. The vulnerability was reserved in March 2025 and published in May 2025, with no patch links currently available, suggesting that mitigation options are limited at this time. The vulnerability is particularly relevant for environments where local users have access to SharePoint servers, such as internal corporate networks or managed service providers.

For European organizations, this vulnerability could lead to significant operational and data security risks. SharePoint is widely used across Europe for collaboration, document management, and intranet services, often hosting sensitive corporate and personal data. Exploitation could allow attackers to execute arbitrary code on SharePoint servers, potentially leading to data breaches, unauthorized data modification, or denial of service. This could disrupt business continuity, damage reputation, and result in regulatory penalties under GDPR if personal data is compromised. The requirement for local access and user interaction somewhat limits remote exploitation but does not eliminate risk, especially in environments with weak endpoint security or insider threats. Organizations in sectors such as finance, government, healthcare, and critical infrastructure, which heavily rely on SharePoint for internal workflows, are particularly vulnerable. The lack of an available patch increases the urgency for interim mitigations to reduce attack surface and exposure.

1. Implement strict access controls to limit local access to SharePoint servers only to trusted administrators and users. 2. Enforce endpoint security measures such as application whitelisting, anti-malware, and behavior monitoring to detect and prevent exploitation attempts. 3. Educate users about the risks of interacting with untrusted data or files that could trigger deserialization attacks, emphasizing caution with suspicious content. 4. Monitor SharePoint server logs and system behavior for unusual activity indicative of exploitation attempts. 5. Isolate SharePoint servers within segmented network zones to reduce lateral movement opportunities. 6. Apply principle of least privilege to all SharePoint-related accounts and services. 7. Stay alert for official patches or updates from Microsoft and plan rapid deployment once available. 8. Consider deploying virtual patching or web application firewalls with custom rules to detect and block suspicious deserialization payloads. 9. Conduct regular security assessments and penetration tests focusing on deserialization and related vulnerabilities. 10. Maintain comprehensive backups of SharePoint data and configurations to enable recovery in case of compromise.