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 attempts to access memory that has already been freed, leading to potential corruption of memory and control flow hijacking. Exploitation requires local access and user interaction, such as opening a specially crafted Word document, but does not require prior authentication. The CVSS v3.1 score of 7.8 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no public exploits are currently known, the vulnerability poses a significant risk due to the widespread use of SharePoint in enterprise environments and the critical role of Word documents in business workflows. The vulnerability was published on July 8, 2025, with a reserved date of June 9, 2025, indicating recent discovery and disclosure. No patches or mitigations have been linked yet, emphasizing the need for immediate attention by affected organizations.

For European organizations, this vulnerability could lead to severe consequences including unauthorized code execution on SharePoint servers or client machines, potentially resulting in data breaches, disruption of collaboration services, and compromise of sensitive corporate information. SharePoint is widely used across Europe for document management and collaboration, making this vulnerability particularly impactful. Attackers exploiting this flaw could gain control over affected systems, leading to lateral movement within networks, data exfiltration, or deployment of ransomware. The requirement for local access and user interaction somewhat limits remote exploitation but does not eliminate risk, especially in environments where users frequently open Word documents from external or untrusted sources. The high confidentiality, integrity, and availability impacts could disrupt business continuity and damage organizational reputation. Additionally, the lack of known exploits currently provides a window for proactive mitigation before active exploitation occurs.

European organizations should immediately implement strict controls on document handling and user privileges. Specific recommendations include: 1) Enforce strict email and document filtering policies to block or quarantine suspicious Word documents, especially those from external sources. 2) Educate users on the risks of opening unsolicited or unexpected Word documents and encourage verification of document sources. 3) Apply application whitelisting to restrict execution of unauthorized code on SharePoint servers and client machines. 4) Use endpoint detection and response (EDR) tools to monitor for anomalous behaviors indicative of use-after-free exploitation attempts. 5) Isolate SharePoint servers in segmented network zones with limited user access to reduce attack surface. 6) Regularly back up SharePoint data and test restoration procedures to mitigate impact of potential compromise. 7) Monitor Microsoft security advisories closely for the release of official patches or workarounds and prioritize their deployment once available. 8) Consider disabling or restricting Word integration features in SharePoint temporarily if feasible until patches are applied.