CVE-2025-29793 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 serialized objects to execute arbitrary code. In this case, the vulnerability permits an attacker with authorized access and high privileges to remotely execute code on the SharePoint server without requiring user interaction. The attack vector is network-based, and the vulnerability impacts confidentiality, integrity, and availability of the system. The CVSS 3.1 score of 7.2 indicates a high severity, with low attack complexity and no user interaction needed, but requiring high privileges. Although no public exploits are known yet, the vulnerability poses a significant risk due to the widespread use of SharePoint in enterprise environments and the critical nature of the data it manages. The vulnerability was reserved in March 2025 and published in April 2025, with no patches currently linked, indicating that organizations must be vigilant for forthcoming updates. The deserialization flaw could allow attackers to execute arbitrary code, potentially leading to full system compromise, data theft, or disruption of services.

For European organizations, the impact of CVE-2025-29793 can be severe. SharePoint is widely used across Europe for document management, collaboration, and enterprise content management, often containing sensitive corporate and governmental data. Exploitation could lead to unauthorized data access, modification, or deletion, undermining data confidentiality and integrity. Availability could also be affected if attackers disrupt SharePoint services or deploy ransomware. Organizations in sectors such as finance, government, healthcare, and critical infrastructure that rely heavily on SharePoint 2016 are particularly at risk. The requirement for high privileges means that insider threats or compromised accounts could be leveraged to exploit this vulnerability. The lack of current public exploits reduces immediate risk but also means attackers may develop exploits once patches are released, increasing the urgency for proactive mitigation. Additionally, the vulnerability could be leveraged as a foothold for lateral movement within networks, amplifying its impact on enterprise environments.

1. Implement the principle of least privilege by restricting SharePoint administrative and high-privilege accounts to only those users who absolutely require them. 2. Monitor and audit privileged account activities closely to detect anomalous behavior indicative of exploitation attempts. 3. Apply network segmentation to limit access to SharePoint servers, reducing exposure to potentially compromised accounts. 4. Deploy application whitelisting and endpoint detection and response (EDR) solutions to identify and block suspicious code execution. 5. Stay alert for official Microsoft patches or security advisories related to this vulnerability and apply updates promptly once available. 6. Consider disabling or restricting features in SharePoint that involve deserialization of data if feasible until patches are applied. 7. Conduct regular security assessments and penetration testing focused on deserialization and privilege escalation vectors. 8. Educate administrators and users about the risks of privilege misuse and the importance of secure credential management. 9. Use multi-factor authentication (MFA) for all privileged accounts to reduce the risk of credential compromise. 10. Maintain comprehensive backups of SharePoint data to enable recovery in case of compromise or data loss.