CVE-2025-54907 is a heap-based buffer overflow vulnerability identified in Microsoft Office 2019, specifically affecting the Visio component. This vulnerability is classified under CWE-122, which pertains to improper handling of memory buffers leading to overflow conditions. The flaw allows an unauthorized attacker to execute arbitrary code locally by exploiting the overflow in the heap memory. The vulnerability requires low attack complexity (AC:L) and no privileges (PR:N), but does require user interaction (UI:R), such as opening a maliciously crafted Visio file. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component without affecting other system components. The vulnerability impacts confidentiality, integrity, and availability at a high level (C:H/I:H/A:H), indicating that successful exploitation can lead to full system compromise, including data theft, modification, or denial of service. The CVSS v3.1 base score is 7.8, categorizing it as a high-severity issue. No known exploits are currently reported in the wild, and no patches have been linked yet, suggesting that mitigation efforts should be prioritized. The vulnerability is present in Microsoft Office 2019 version 19.0.0. Given the nature of the vulnerability, attackers could craft malicious Visio files that, when opened by a user, trigger the buffer overflow, leading to arbitrary code execution with the privileges of the user. This local code execution could be leveraged for privilege escalation or lateral movement within an organization’s network if combined with other vulnerabilities or misconfigurations.

For European organizations, the impact of CVE-2025-54907 is significant due to the widespread use of Microsoft Office 2019 across various sectors including government, finance, healthcare, and critical infrastructure. Successful exploitation could lead to unauthorized access to sensitive data, disruption of business operations, and potential compromise of network integrity. The requirement for user interaction means phishing or social engineering campaigns could be used to deliver malicious Visio files, increasing the risk in environments where employees frequently exchange documents. Given the high confidentiality, integrity, and availability impacts, organizations could face regulatory consequences under GDPR if personal data is compromised. Additionally, disruption to critical services could have broader societal impacts, especially in sectors like healthcare or public administration. The lack of known exploits in the wild currently provides a window for proactive defense, but the high severity score necessitates urgent attention to prevent potential future exploitation.

1. Implement strict email filtering and attachment scanning to detect and block malicious Visio files before they reach end users. 2. Educate users on the risks of opening unsolicited or unexpected Visio documents, emphasizing caution with files from unknown or untrusted sources. 3. Employ application whitelisting and sandboxing techniques to restrict execution of untrusted code and isolate Office applications. 4. Monitor endpoint behavior for signs of exploitation attempts, such as unusual memory usage or process spawning linked to Visio. 5. Maintain up-to-date backups and ensure incident response plans include scenarios involving local code execution vulnerabilities. 6. Once available, promptly apply official patches or updates from Microsoft addressing this vulnerability. 7. Use endpoint detection and response (EDR) tools to detect and block exploitation attempts leveraging this vulnerability. 8. Limit user privileges to the minimum necessary to reduce the impact of local code execution attacks.