CVE-2025-54902 is an out-of-bounds read vulnerability categorized under CWE-125 affecting Microsoft Excel in Microsoft 365 Apps for Enterprise version 16.0.1. This vulnerability arises when Excel improperly handles memory bounds during file processing, allowing an attacker to read memory outside the intended buffer. Exploitation can lead to local code execution without requiring prior privileges, but it does require user interaction, such as opening a specially crafted malicious Excel document. The vulnerability affects confidentiality, integrity, and availability by potentially allowing arbitrary code execution, which could lead to full system compromise. The CVSS 3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, and user interaction needed. The scope is unchanged, meaning the impact is limited to the vulnerable component. No patches were linked at the time of publication, and no known exploits have been observed in the wild. Given Microsoft 365's extensive deployment in enterprise environments globally, this vulnerability poses a significant risk if weaponized. The vulnerability was reserved in late July 2025 and published in early September 2025, indicating a relatively recent discovery.

The vulnerability allows attackers to execute arbitrary code locally on affected systems, potentially leading to full compromise of the user's machine. This can result in unauthorized access to sensitive data, disruption of business operations, and the deployment of malware or ransomware. Since Microsoft 365 Apps for Enterprise is widely used in corporate environments, the impact could be widespread, affecting confidentiality, integrity, and availability of enterprise data and systems. The requirement for user interaction (opening a malicious file) limits remote exploitation but does not eliminate risk, especially in environments where phishing attacks are common. The lack of required privileges means any user can be targeted, increasing the attack surface. Organizations relying heavily on Excel for critical business processes are particularly vulnerable to operational disruptions and data breaches stemming from this flaw.

Organizations should prioritize deploying official patches from Microsoft as soon as they become available to remediate this vulnerability. Until patches are released, implement strict email and file filtering to block or quarantine suspicious Excel files, especially those from untrusted sources. Employ application whitelisting and sandboxing to restrict the execution of untrusted code and limit the impact of potential exploitation. Educate users about the risks of opening unsolicited or unexpected Excel attachments, emphasizing caution with files from unknown senders. Utilize endpoint detection and response (EDR) solutions to monitor for anomalous behavior indicative of exploitation attempts. Consider disabling macros and other potentially risky Excel features if not required. Regularly update and audit security policies related to document handling and user privileges to reduce exposure. Maintain robust backup and recovery procedures to mitigate damage from potential attacks leveraging this vulnerability.