CVE-2025-49712 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 deserialized by an application, potentially allowing attackers to manipulate the process to execute arbitrary code. In this case, an attacker with authorized access to the SharePoint server can send specially crafted serialized data over the network, which the server improperly deserializes, leading to remote code execution (RCE). The vulnerability requires low privileges (PR:L), no user interaction (UI:N), and can be exploited remotely over the network (AV:N). The CVSS v3.1 base score is 8.8, indicating high severity with critical impacts on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability is currently published but lacks known exploits in the wild, suggesting it is either newly discovered or not yet weaponized. The absence of patches at the time of reporting means organizations must rely on compensating controls until updates are released. This vulnerability is particularly dangerous because SharePoint servers often hold sensitive corporate data and are integrated into enterprise workflows, making successful exploitation highly impactful.

For European organizations, exploitation of CVE-2025-49712 could lead to full compromise of SharePoint servers, resulting in unauthorized access to sensitive documents, disruption of collaboration services, and potential lateral movement within corporate networks. The breach of confidentiality could expose intellectual property, personal data protected under GDPR, and strategic business information. Integrity and availability impacts could disrupt business operations, cause data corruption, or enable ransomware deployment. Given the widespread use of SharePoint in European enterprises and public sector organizations, the threat could affect critical infrastructure, government agencies, and large corporations. The network-based exploitability and lack of required user interaction increase the risk of rapid spread and automated attacks if weaponized. The potential regulatory and reputational consequences for European entities are significant, especially under stringent data protection laws.

1. Monitor Microsoft’s security advisories closely and apply patches for SharePoint Enterprise Server 2016 as soon as they become available. 2. Restrict network access to SharePoint servers using firewalls and network segmentation, limiting exposure to only trusted internal users and systems. 3. Enforce the principle of least privilege by reviewing and minimizing user permissions on SharePoint environments to reduce the pool of authorized attackers. 4. Implement application-layer filtering and input validation where possible to detect and block malformed serialized data. 5. Enable and review detailed logging and monitoring on SharePoint servers to detect anomalous deserialization activities or unexpected code execution attempts. 6. Conduct regular vulnerability scans and penetration tests focusing on deserialization and remote code execution vectors. 7. Educate administrators and security teams about this vulnerability to ensure rapid incident response readiness. 8. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect exploitation attempts targeting deserialization flaws.