CVE-2025-29976 is a high-severity vulnerability classified under CWE-269 (Improper Privilege Management) affecting Microsoft SharePoint Enterprise Server 2016, specifically version 16.0.0. The vulnerability allows an authorized attacker—meaning someone who already has some level of access—to locally elevate their privileges beyond what should be permitted. This elevation could enable the attacker to gain administrative or other high-level privileges on the SharePoint server, potentially allowing them to execute unauthorized actions, access sensitive data, modify configurations, or disrupt services. The CVSS 3.1 base score of 7.8 reflects the significant impact on confidentiality, integrity, and availability, with the attack vector being local (AV:L), requiring low attack complexity (AC:L), and low privileges (PR:L) but no user interaction (UI:N). The scope remains unchanged (S:U), indicating the vulnerability affects only the SharePoint component itself. Although no known exploits are currently in the wild, the vulnerability’s characteristics suggest that once exploited, it could severely compromise the affected SharePoint environment. The lack of available patches at the time of publication increases the urgency for mitigation and monitoring. Given SharePoint’s role as a collaboration and document management platform widely used in enterprises, this vulnerability poses a significant risk to organizations relying on SharePoint for sensitive business processes and data storage.

For European organizations, the impact of CVE-2025-29976 could be substantial. SharePoint Enterprise Server 2016 is commonly deployed in medium to large enterprises across Europe for internal collaboration, document management, and workflow automation. An attacker exploiting this vulnerability could escalate privileges locally, potentially gaining administrative control over SharePoint environments. This could lead to unauthorized access to confidential corporate data, intellectual property, and personal data protected under GDPR. The integrity of business-critical documents and workflows could be compromised, leading to operational disruptions and reputational damage. Additionally, availability could be affected if attackers modify or delete critical content or configurations. Given the strict regulatory environment in Europe, such breaches could also result in significant legal and financial penalties. The local attack vector implies that attackers need some initial access, which could be obtained through compromised user credentials or insider threats, making internal security controls and monitoring crucial.

To mitigate CVE-2025-29976 effectively, European organizations should implement a multi-layered approach: 1) Restrict local access to SharePoint servers strictly to trusted administrators and service accounts; 2) Enforce the principle of least privilege rigorously, ensuring users and service accounts have only the minimum necessary permissions; 3) Monitor and audit privilege changes and access logs on SharePoint servers to detect suspicious privilege escalations promptly; 4) Apply network segmentation to isolate SharePoint servers from less trusted network zones; 5) Implement strong authentication mechanisms, such as multi-factor authentication, for all users with access to SharePoint environments; 6) Since no patches are currently available, consider temporary compensating controls such as disabling unnecessary local accounts or services that could be leveraged for privilege escalation; 7) Prepare for rapid deployment of official patches once released by Microsoft and test them in controlled environments before production rollout; 8) Conduct regular security awareness training to reduce the risk of credential compromise that could enable local access; 9) Employ endpoint detection and response (EDR) solutions on SharePoint servers to identify and respond to suspicious activities indicative of privilege escalation attempts.