A null pointer dereference flaw in SumatraPDF 3.5.2 could lead to a denial of service if an attacker provides a specially crafted .djvu file.

The vulnerability is a null pointer dereference occurring within the DataPool::has_data() function in libmupdf.dll. The issue is triggered when an unauthenticated user opens a malicious .djvu file, causing the application to crash.

The primary impact of this vulnerability is the potential for service disruption, as a successful exploit causes the SumatraPDF application to crash. While the CVSS score of 7.3 indicates a High severity, the impact is primarily focused on availability rather than unauthorized data access or code execution. Organizations relying on this software for critical document processing may face workflow interruptions if users are induced to open malicious files.

Immediate Action: Users should exercise caution when opening untrusted .djvu files until a formal patch is released by the vendor. Monitor the official SumatraPDF GitHub repository for updates regarding version 3.5.3 or later.

Proactive Monitoring: Security teams should review endpoint logs for recurring application crashes associated with SumatraPDF, which may indicate attempted exploitation.

Compensating Controls: Deploy endpoint security solutions that can scan incoming documents for malicious patterns before they reach the end user environment.

Public Exploit Available: Unknown.

Given the availability of a proof-of-concept, administrators should prioritize restricting the ability of users to open untrusted .djvu files from external sources. Organizations should maintain vigilance and apply the vendor patch as soon as it is made available to fully remediate the underlying crash condition.