CVE-2025-62201 is a heap-based buffer overflow vulnerability classified under CWE-122 affecting Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise version 16.0.1. The vulnerability arises from improper handling of heap memory during processing of specially crafted Excel files, which can lead to memory corruption. An attacker can exploit this flaw by convincing a user to open a malicious Excel document, triggering the overflow and enabling arbitrary code execution with the privileges of the current user. The vulnerability does not require prior authentication but does require user interaction (opening the file). The CVSS v3.1 base score is 7.8, reflecting high severity due to the potential for full system compromise (confidentiality, integrity, and availability impacts). No patches have been linked yet, and no exploits are known to be active in the wild as of the publication date. The vulnerability was reserved on October 8, 2025, and published on November 11, 2025. Given the widespread use of Microsoft 365 Apps, this vulnerability poses a significant risk to enterprise environments, especially those heavily reliant on Excel for business-critical operations.

If exploited, this vulnerability allows attackers to execute arbitrary code locally, potentially leading to full system compromise. This can result in unauthorized data access, data corruption, or disruption of services. Since the attack vector requires user interaction, phishing or social engineering campaigns could be used to deliver malicious Excel files. Organizations could face data breaches, loss of intellectual property, operational downtime, and reputational damage. The high severity and the common use of Microsoft 365 Apps in enterprises worldwide amplify the potential impact. Additionally, the vulnerability affects confidentiality, integrity, and availability, making it a comprehensive threat to affected systems.

Until an official patch is released, organizations should implement the following mitigations: 1) Enforce strict email filtering and attachment scanning to block or quarantine suspicious Excel files. 2) Educate users to avoid opening unsolicited or unexpected Excel documents, especially from unknown sources. 3) Utilize application whitelisting or sandboxing to restrict execution of untrusted Office macros or code. 4) Enable Microsoft Defender Exploit Guard and other endpoint protection features that can detect and block exploitation attempts. 5) Monitor network and endpoint logs for unusual Excel process behavior or crashes indicative of exploitation attempts. 6) Once available, promptly apply official patches from Microsoft to remediate the vulnerability. 7) Consider disabling legacy or unnecessary Office features that increase attack surface, such as macros or external content in Excel files.