CVE-2025-62558 is a use-after-free vulnerability classified under CWE-416 affecting Microsoft SharePoint Enterprise Server 2016, specifically version 16.0.0. The flaw originates from improper memory management in Microsoft Office Word components integrated with SharePoint, allowing an attacker to execute arbitrary code locally. The vulnerability does not require prior authentication but does require user interaction, such as opening a malicious document or triggering a crafted payload. The CVSS 3.1 base score of 7.8 reflects high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. The vulnerability was reserved in mid-October 2025 and published in December 2025, with no patches or known exploits publicly available at the time of analysis. Exploitation could lead to full system compromise of the affected SharePoint server, enabling attackers to manipulate sensitive data, disrupt services, or pivot within the network. The use-after-free condition arises when the application frees memory but continues to use the dangling pointer, leading to unpredictable behavior exploitable for code execution. Due to SharePoint's widespread use in enterprise environments for document management and collaboration, this vulnerability presents a significant threat vector if weaponized.

For European organizations, the impact of CVE-2025-62558 could be severe, especially for those relying heavily on Microsoft SharePoint Enterprise Server 2016 for document collaboration and storage. Successful exploitation could lead to unauthorized code execution on critical servers, potentially compromising sensitive corporate or governmental data, disrupting business operations, and enabling lateral movement within networks. Confidentiality breaches could expose intellectual property or personal data protected under GDPR, leading to regulatory penalties. Integrity violations might result in tampered documents or corrupted workflows, while availability impacts could disrupt essential services. Given the vulnerability requires user interaction but no authentication, phishing or social engineering campaigns could be effective attack vectors. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly at risk due to the strategic importance of their data and services. The lack of known exploits currently provides a window for proactive defense, but the high severity score indicates urgency in mitigation.

1. Immediately assess the deployment of Microsoft SharePoint Enterprise Server 2016 (version 16.0.0) within the organization and prioritize systems handling sensitive or critical data. 2. Monitor Microsoft security advisories closely for official patches or updates addressing CVE-2025-62558 and apply them promptly once available. 3. Until patches are released, consider disabling or restricting features that invoke Microsoft Office Word rendering within SharePoint to reduce attack surface. 4. Implement strict user training and awareness programs to reduce the risk of social engineering attacks that could trigger the vulnerability. 5. Employ application whitelisting and endpoint protection solutions capable of detecting anomalous behaviors related to use-after-free exploitation. 6. Use network segmentation to isolate SharePoint servers from less trusted network segments and limit lateral movement opportunities. 7. Enable detailed logging and monitoring on SharePoint servers to detect unusual activities indicative of exploitation attempts. 8. Review and enforce least privilege principles for users interacting with SharePoint to minimize potential damage from compromised accounts. 9. Conduct regular vulnerability scans and penetration tests focusing on SharePoint environments to identify and remediate weaknesses proactively.