CVE-2025-49703 is a high-severity use-after-free vulnerability (CWE-416) affecting Microsoft SharePoint Enterprise Server 2016, specifically version 16.0.0. The vulnerability arises from improper handling of memory in Microsoft Office Word components integrated with SharePoint, allowing an unauthorized attacker to execute arbitrary code locally. The flaw occurs when the application accesses memory after it has been freed, potentially leading to memory corruption. Exploitation requires local access and user interaction, such as opening a specially crafted document, but does not require privileges or authentication. The CVSS 3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no known exploits are currently reported in the wild, the vulnerability poses a significant risk due to the critical nature of SharePoint in enterprise environments and the potential for privilege escalation or lateral movement if exploited. The vulnerability was published on July 8, 2025, with no patches currently available, increasing the urgency for mitigation.

For European organizations, this vulnerability presents a substantial risk, especially for enterprises relying on SharePoint Enterprise Server 2016 for document management and collaboration. Successful exploitation could lead to unauthorized code execution on critical servers, compromising sensitive corporate data, intellectual property, and potentially enabling attackers to move laterally within networks. The impact on confidentiality is high due to potential data exposure; integrity is compromised by possible unauthorized changes to documents or configurations; and availability could be affected if the exploit causes system crashes or service disruptions. Given the widespread use of Microsoft SharePoint across European public and private sectors, including government agencies, financial institutions, and large enterprises, the vulnerability could facilitate targeted attacks or ransomware deployment. The requirement for local access and user interaction somewhat limits remote exploitation but does not eliminate risk, as phishing or social engineering could be used to trick users into opening malicious documents.

Immediate mitigation steps include restricting local access to SharePoint servers and educating users about the risks of opening untrusted documents. Organizations should implement strict endpoint protection and application whitelisting to prevent execution of unauthorized code. Network segmentation can limit lateral movement if exploitation occurs. Monitoring and logging should be enhanced to detect suspicious activity related to document handling and memory corruption attempts. Since no official patch is currently available, organizations should consider disabling or restricting Microsoft Office Word integration with SharePoint where feasible, or deploying virtualized environments for document processing to contain potential exploits. Regular backups and incident response plans should be reviewed and updated to prepare for possible exploitation. Additionally, organizations should subscribe to Microsoft security advisories to apply patches immediately upon release.