CVE-2025-27745 is a use-after-free vulnerability classified under CWE-416 affecting Microsoft 365 Apps for Enterprise, specifically version 16.0.1. This vulnerability arises when the application improperly manages memory, freeing an object while it is still accessible, which can lead to execution of arbitrary code by an attacker. The flaw allows an unauthorized attacker to execute code locally on the affected system, potentially leading to full compromise of the user’s session. The CVSS 3.1 base score of 7.8 indicates a high-severity issue, with an attack vector of local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No known exploits are currently reported in the wild, but the vulnerability’s nature suggests that exploitation could be achieved through crafted malicious documents or files opened by the user. Since the vulnerability affects a widely used productivity suite, it poses a significant risk to enterprise environments. Microsoft has not yet published patches at the time of this report, but organizations should monitor for updates and prepare to deploy them promptly. The vulnerability’s exploitation requires local access and user interaction, which somewhat limits remote exploitation but does not eliminate risk, especially in environments where users may be tricked into opening malicious files. The vulnerability’s presence in a core productivity tool used extensively in business environments underscores the importance of rapid mitigation and defense-in-depth strategies.

For European organizations, the impact of CVE-2025-27745 could be substantial due to the widespread use of Microsoft 365 Apps for Enterprise in business, government, and critical infrastructure sectors. Successful exploitation could lead to unauthorized code execution on user machines, enabling attackers to steal sensitive data, disrupt operations, or move laterally within networks. The high impact on confidentiality, integrity, and availability means that data breaches, ransomware deployment, or system sabotage are plausible outcomes. Given the local attack vector and requirement for user interaction, phishing or social engineering campaigns could be leveraged to trigger exploitation. This vulnerability could particularly affect sectors with high reliance on Microsoft Office productivity tools, such as finance, healthcare, manufacturing, and public administration. The potential for privilege escalation or persistence through this vulnerability could also facilitate more advanced attacks. The absence of known exploits in the wild currently provides a window for proactive defense, but the risk remains elevated until patches are applied and mitigations are in place.

1. Monitor Microsoft security advisories closely and apply official patches for Microsoft 365 Apps for Enterprise version 16.0.1 immediately upon release. 2. Implement strict application control policies (e.g., Microsoft AppLocker or Windows Defender Application Control) to restrict execution of unauthorized or suspicious code on endpoints. 3. Enforce the principle of least privilege for users to limit the impact of local code execution vulnerabilities. 4. Conduct user awareness training focused on recognizing phishing attempts and avoiding opening untrusted or unexpected Office documents. 5. Utilize endpoint detection and response (EDR) solutions to monitor for anomalous behaviors indicative of exploitation attempts, such as unusual Office process activity or memory manipulation. 6. Employ network segmentation to limit lateral movement opportunities if a local compromise occurs. 7. Disable or restrict macros and other potentially risky Office features where possible. 8. Regularly back up critical data and verify the integrity of backups to enable recovery in case of compromise. 9. Consider deploying exploit mitigation technologies such as Control Flow Guard (CFG) and Data Execution Prevention (DEP) to reduce exploitation success likelihood. 10. Review and update incident response plans to incorporate scenarios involving local code execution vulnerabilities in productivity software.