CVE-2025-53784 is a high-severity use-after-free vulnerability (CWE-416) identified in Microsoft 365 Apps for Enterprise, specifically affecting Microsoft Office Word version 16.0.1. A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, leading to undefined behavior including potential arbitrary code execution. In this case, the vulnerability allows an unauthorized attacker to execute code locally without requiring any user interaction or privileges. The CVSS 3.1 base score is 8.4, reflecting a high impact on confidentiality, integrity, and availability. The attack vector is local (AV:L), meaning the attacker must have local access to the system. However, no privileges or user interaction are required (PR:N/UI:N), which increases the risk if an attacker gains local access through other means. Exploitation could lead to full compromise of the affected system, allowing an attacker to execute arbitrary code with the same privileges as the user running Microsoft Word. Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a significant threat if weaponized. The vulnerability was reserved in early July 2025 and published in August 2025, with no patch links currently available, indicating that mitigation may rely on workarounds or upcoming updates from Microsoft.

For European organizations, this vulnerability poses a serious risk particularly in environments where Microsoft 365 Apps for Enterprise is widely deployed, such as corporate offices, government agencies, and educational institutions. The ability for an attacker to execute code locally without user interaction or privileges means that any compromise of local access—through insider threats, physical access, or other malware—could be escalated to full system compromise. This could lead to data breaches, ransomware deployment, or lateral movement within networks. Confidentiality is at high risk due to potential data exfiltration; integrity is compromised by possible unauthorized code execution; and availability could be affected if systems are destabilized or taken offline. Given the prevalence of Microsoft Office in European enterprises, the vulnerability could have widespread impact if exploited. The lack of known exploits in the wild currently provides a window for organizations to prepare and mitigate before active attacks emerge.

1. Immediate mitigation should focus on restricting local access to systems running Microsoft 365 Apps for Enterprise, especially version 16.0.1, through strict physical security controls and endpoint access management. 2. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious local code execution attempts. 3. Disable or limit the use of Microsoft Word macros and embedded content that could trigger the vulnerability. 4. Monitor for unusual local activity or privilege escalations that could indicate exploitation attempts. 5. Stay alert for official patches or security updates from Microsoft and apply them promptly once available. 6. Implement network segmentation to limit lateral movement if a local compromise occurs. 7. Educate employees about the risks of local system access and enforce least privilege principles to reduce the attack surface. 8. Consider deploying virtual desktop infrastructure (VDI) or sandbox environments for handling untrusted documents to contain potential exploitation.