CVE-2025-32704: Buffer Over-read Vulnerability in Microsoft Office Excel

Overview

The vulnerability CVE-2025-32704 is a critical issue that affects Microsoft Office Excel, a widely used spreadsheet program. This security flaw, classified as a buffer over-read vulnerability, can potentially allow an unauthorized attacker to execute arbitrary code on the victim’s system. As such, the severity and potential impact of this vulnerability cannot be overstated. A successful attack could lead to system compromise or data leakage, posing significant risks to businesses and individuals alike.

Vulnerability Summary

CVE ID: CVE-2025-32704
Severity: Critical, CVSS Score 8.4
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office Excel | All versions prior to patch

How the Exploit Works

The exploit hinges on a buffer over-read vulnerability in Microsoft Office Excel. Buffer over-read is a type of security flaw that occurs when a program reads beyond the boundary of a buffer. This can happen due to coding errors when manipulating data in the buffer. In this case, an attacker could craft a malicious Excel file that, when opened, triggers the buffer over-read, allowing the attacker to execute arbitrary code on the victim’s system.

Conceptual Example Code

This is a conceptual example of an exploit that could potentially take advantage of the vulnerability. It assumes that the attacker has created a malicious Excel file with embedded code.

# Attacker crafts malicious Excel file
echo "malicious_code" > exploit.xls
# Attacker sends file to victim
scp exploit.xls victim@target:/tmp/
# Victim opens the file in Excel, triggering the exploit
victim$ excel /tmp/exploit.xls

Please note that this is a simplified example for illustrative purposes and the actual attack would likely involve more complex and obfuscated code.

Mitigation Guidance

The best way to mitigate this vulnerability is to apply the vendor-provided patch as soon as it becomes available. In the meantime, users can use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as temporary mitigation. It is also advisable to be wary of any unsolicited Excel files and to avoid opening any from untrusted sources.