CVE-2025-59234 is a use-after-free vulnerability classified under CWE-416 affecting Microsoft Office 2016, specifically version 16.0.0. This vulnerability arises when the software improperly manages memory, freeing an object while it is still in use, which can lead to execution of arbitrary code by an attacker. The flaw allows an unauthorized attacker to execute code locally on the victim’s machine, potentially leading to full compromise of the system’s confidentiality, integrity, and availability. Exploitation requires user interaction, such as opening a malicious document, but does not require any privileges or authentication, making it accessible to a wide range of attackers. The CVSS v3.1 score of 7.8 reflects a high severity, with attack vector local, low attack complexity, no privileges required, and user interaction needed. The vulnerability is currently published with no known exploits in the wild and no patches released yet, increasing the urgency for defensive measures. The lack of patch links suggests that organizations must rely on interim mitigations until an official fix is available. Given Microsoft Office 2016’s extensive use in enterprise environments, this vulnerability poses a significant risk, especially in sectors reliant on document processing and collaboration tools.

For European organizations, this vulnerability presents a serious risk of local code execution leading to potential full system compromise. Confidential data processed or stored within Office documents could be exposed or altered, impacting data confidentiality and integrity. The availability of affected systems could also be disrupted if attackers leverage the vulnerability to execute destructive payloads. Given the widespread use of Microsoft Office 2016 across European enterprises, government agencies, and critical infrastructure operators, exploitation could result in operational disruptions and data breaches. The requirement for user interaction means phishing or social engineering campaigns could be used to deliver malicious documents, increasing the attack surface. The absence of known exploits in the wild currently limits immediate risk, but the high severity and lack of patches necessitate proactive defense. Organizations in sectors such as finance, healthcare, and public administration are particularly vulnerable due to the sensitivity of their data and reliance on Office applications.

1. Immediately restrict or monitor the use of Microsoft Office 2016 version 16.0.0 within the organization, especially on high-risk endpoints. 2. Educate users to be vigilant against opening unsolicited or suspicious Office documents, emphasizing the risk of social engineering attacks. 3. Deploy application whitelisting and endpoint protection solutions capable of detecting anomalous behaviors associated with exploitation attempts. 4. Implement network segmentation to limit lateral movement if a system is compromised. 5. Monitor for unusual process creation or memory usage patterns indicative of exploitation attempts. 6. Prepare for rapid deployment of official patches once released by Microsoft by establishing a prioritized patch management process. 7. Consider upgrading to a supported and patched version of Microsoft Office where feasible to reduce exposure. 8. Use email filtering and sandboxing technologies to detect and block malicious Office documents before reaching end users. 9. Regularly back up critical data and verify the integrity of backups to enable recovery in case of compromise.