CVE-2025-49712 is a high-severity vulnerability identified in Microsoft SharePoint Enterprise Server 2016 (version 16.0.0). It is classified under CWE-502, which pertains to the deserialization of untrusted data. Deserialization vulnerabilities occur when an application deserializes data from an untrusted source without sufficient validation, allowing attackers to manipulate the serialized data to execute arbitrary code. In this case, the vulnerability allows an authorized attacker—meaning one with legitimate access privileges—to execute arbitrary code remotely over the network without requiring user interaction. The CVSS v3.1 score of 8.8 reflects the critical nature of this flaw, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). This vulnerability could enable attackers to fully compromise affected SharePoint servers, potentially leading to data breaches, service disruption, or lateral movement within an enterprise network. Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a significant risk if weaponized. The absence of published patches at the time of disclosure increases the urgency for mitigation and monitoring.

For European organizations, the impact of CVE-2025-49712 could be substantial. SharePoint Enterprise Server 2016 is widely used across various sectors including government, finance, healthcare, and large enterprises for document management and collaboration. Exploitation could lead to unauthorized code execution on critical servers, resulting in data theft, alteration, or destruction. This could compromise sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. Additionally, the ability to execute code remotely without user interaction increases the risk of rapid propagation of attacks, potentially disrupting business continuity and critical services. Given the interconnected nature of European enterprise networks and the reliance on SharePoint for internal workflows, a successful attack could also facilitate lateral movement, escalating the breach impact across multiple systems and subsidiaries within multinational organizations.

Organizations should prioritize the following specific mitigation steps: 1) Conduct an immediate inventory to identify all instances of Microsoft SharePoint Enterprise Server 2016 version 16.0.0 in their environment. 2) Monitor official Microsoft channels closely for the release of security patches addressing CVE-2025-49712 and apply them promptly upon availability. 3) Restrict access to SharePoint servers to only necessary authorized users and implement strict privilege management to minimize the number of users with elevated rights. 4) Employ network segmentation and firewall rules to limit exposure of SharePoint servers to untrusted networks. 5) Enable and review detailed logging and monitoring on SharePoint servers to detect unusual activities indicative of exploitation attempts. 6) Consider deploying application-layer firewalls or intrusion prevention systems with updated signatures to detect and block malicious deserialization payloads. 7) Conduct targeted security assessments and penetration testing focused on deserialization attack vectors to identify and remediate potential weaknesses. 8) Educate administrators and users about the risks associated with deserialization vulnerabilities and the importance of adhering to security best practices.