CVE-2025-53733: Microsoft Office Word Numeric Type Conversion Vulnerability

Overview

In the world of cybersecurity, a newly discovered vulnerability has emerged that affects Microsoft Office Word, a widely used software by individuals and organizations alike. The vulnerability, dubbed CVE-2025-53733, arises from an incorrect conversion between numeric types within the software, opening opportunities for attackers to execute code locally on the victim’s system. Given the prevalence of Microsoft Office Word and the severity of this vulnerability, it is a significant concern for both individual users and IT administrators.

Vulnerability Summary

CVE ID: CVE-2025-53733
Severity: High (8.4 CVSS Score)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: Successful exploitation of this vulnerability could lead to system compromise or data leakage.

Affected Products

Product | Affected Versions

Microsoft Office Word | All versions up to and including the latest version at the time of the vulnerability discovery.

How the Exploit Works

The exploit works by exploiting an incorrect conversion between numeric types in Microsoft Word. Specifically, an attacker crafts a specially formatted file that, when opened in Microsoft Word, triggers the flaw, allowing the attacker to execute arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system.

Conceptual Example Code

The following is a conceptual example of how the vulnerability might be exploited using a malicious Word document:

# Attacker creates a malicious Word document
echo "{ malicious_code: '...'}" > exploit.docx
# Attacker sends the malicious document to the victim
mail -s "Important Document" victim@example.com < exploit.docx

In this example, the attacker creates a malicious Word document containing the exploit code and sends it to the victim via email. If the victim opens the document, the exploit code is executed, potentially compromising the system or leading to data leakage.

Mitigation Guidance

Users and administrators are advised to apply the latest patches from Microsoft for Office Word as soon as they become available. Until the patch is available or applied, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used as a temporary mitigation to detect and potentially block attempts to exploit this vulnerability. Furthermore, users should be wary of opening Word documents from untrusted sources, as they could contain malicious code exploiting this vulnerability.