Overview
This report addresses the critical vulnerability, CVE-2025-54898, a serious out-of-bounds read flaw found in Microsoft Office Excel. This vulnerability, if exploited, could allow an unauthorized attacker to execute arbitrary code on the target system. Considering the wide usage of Microsoft Office Excel across various sectors, such a vulnerability could have significant implications, potentially leading to a compromise of systems or leakage of confidential data.
Vulnerability Summary
CVE ID: CVE-2025-54898
Severity: High (CVSS: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
    
      
    
    Escape the Surveillance Era
  
  
    Most apps won’t tell you the truth.
 
	  They’re part of the problem.
    Phone numbers. Emails. Profiles. Logs.
    It’s all fuel for surveillance.
  
Ameeba Chat gives you a way out.
- • No phone number
 - • No email
 - • No personal info
 - • Anonymous aliases
 - • End-to-end encrypted
 
Chat without a trace.
Product | Affected Versions
Microsoft Office Excel | All versions until patched
How the Exploit Works
The vulnerability is an out-of-bounds read error within Microsoft Office Excel. This occurs when the application attempts to read data that is outside the intended boundary of a buffer. An attacker could craft a malicious Excel file that, when opened by the user, exploits this vulnerability to execute arbitrary code. This code execution occurs in the context of the current user and could lead to a complete compromise of the affected system.
Conceptual Example Code
The following is a conceptual example of how the vulnerability might be exploited via a malicious Excel file:
POST /upload_file HTTP/1.1
Host: target.example.com
Content-Type: application/vnd.ms-excel
{ "file": "<base64_encoded_malicious_excel_file>" }
Please note that this is a simplified example and the actual exploit would involve crafting a specific Excel file to trigger the out-of-bounds read.
Recommendations
To mitigate this vulnerability, users are advised to apply the latest vendor patch provided by Microsoft. In the absence of a patch, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as temporary mitigation methods. However, these are not foolproof and can only serve to detect or prevent known exploitation techniques. Therefore, the application of the vendor patch remains the most effective mitigation strategy.

