CVE-2025-54901 is a medium-severity vulnerability identified in Microsoft Office 2019, specifically affecting the Excel component (version 19.0.0). The vulnerability is classified as a buffer over-read (CWE-126), which occurs when a program reads data beyond the boundaries of a buffer. In this case, the flaw allows an unauthorized attacker to cause Microsoft Excel to read beyond allocated memory buffers, potentially disclosing sensitive information locally. The vulnerability does not require privileges (PR:N) but does require user interaction (UI:R), meaning the attacker must convince the user to open a malicious or crafted Excel file. The attack vector is local (AV:L), so the attacker must have local access to the system or trick the user into opening a malicious file. The impact is primarily on confidentiality (C:H), with no impact on integrity or availability. There are no known exploits in the wild at the time of publication, and no patches have been linked yet. The vulnerability was reserved on July 31, 2025, and published on September 9, 2025. The CVSS v3.1 base score is 5.5, reflecting a medium severity level. This vulnerability could allow attackers to read sensitive information from memory, which might include data from other processes or sensitive Excel document contents, potentially leading to information disclosure and privacy breaches. Since the attack requires user interaction and local access, it is less likely to be exploited remotely but remains a risk in environments where malicious files can be introduced or users are tricked into opening compromised documents.

For European organizations, the impact of CVE-2025-54901 could be significant in sectors where Microsoft Office 2019 is widely used, such as government, finance, healthcare, and legal industries. The information disclosure risk could lead to leakage of confidential business data, personal data protected under GDPR, or intellectual property. Although the vulnerability requires local access and user interaction, phishing campaigns or insider threats could exploit this vector. The confidentiality breach could undermine trust, lead to regulatory penalties under GDPR for data leaks, and cause reputational damage. Since Microsoft Office is a standard productivity tool across Europe, the vulnerability could affect a broad range of organizations, especially those with less mature endpoint security or user awareness programs. The lack of known exploits in the wild currently reduces immediate risk, but the medium severity and potential for sensitive data exposure warrant proactive mitigation.

European organizations should implement a multi-layered mitigation approach: 1) Educate users to avoid opening Excel files from untrusted or unknown sources to reduce the risk of user interaction exploitation. 2) Employ endpoint protection solutions that can detect and block malicious document behavior or suspicious file access patterns. 3) Monitor local systems for unusual memory access or application crashes related to Excel. 4) Apply principle of least privilege to limit local user permissions and reduce the attack surface. 5) Once Microsoft releases an official patch, prioritize its deployment across all affected systems. 6) Use application whitelisting and sandboxing to restrict execution of untrusted Office documents. 7) Implement network segmentation to limit lateral movement if local compromise occurs. 8) Maintain up-to-date backups to recover from any potential data exposure consequences. These steps go beyond generic advice by focusing on user training, endpoint detection, and access controls tailored to the nature of this local, user-interaction-based vulnerability.