CVE-2025-54900: 
vulnerability analysis and mitigation

CVE-2025-54900 is a Remote Code Execution (RCE) vulnerability in Microsoft Excel that was patched as part of Microsoft's September 2025 Patch Tuesday security updates. The vulnerability is classified as Important severity and involves a heap-based buffer overflow in Microsoft Excel that allows for local code execution (Cybersecurity News, GBHackers).

The vulnerability is caused by a heap-based buffer overflow condition in Microsoft Excel that could allow an attacker to execute arbitrary code in the context of the current user. The vulnerability has been assigned an Important severity rating rather than Critical, suggesting some mitigating factors in its exploitation. No CVSS score has been publicly disclosed for this specific vulnerability (Bleeping Computer).

If successfully exploited, this vulnerability allows an attacker to execute malicious code locally on the affected system through Microsoft Excel. The attacker would gain the same rights as the currently logged-in user, potentially allowing them to install programs, view, change, or delete data, or create new accounts with full user rights if the current user has administrative privileges (Cybersecurity News).

Microsoft has released a security patch for this vulnerability as part of the September 2025 Patch Tuesday updates. Organizations are strongly urged to apply the security updates promptly to mitigate the risk. As a general security practice, users should be cautious when opening Excel files from untrusted sources (Bleeping Computer).