CVE-2021-26237 : Vulnerability Insights and Analysis

FastStone Image Viewer <= 7.5 is affected by a user mode write access violation at 0x00402d7d, triggered when a user opens or views a malformed CUR file that is mishandled by FSViewer.exe. This vulnerability could be exploited by attackers to cause a Denial of Service (DoS) or potentially execute arbitrary code.

Understanding CVE-2021-26237

This section provides an overview of the CVE-2021-26237 vulnerability in FastStone Image Viewer.

What is CVE-2021-26237?

CVE-2021-26237 is a security vulnerability in FastStone Image Viewer versions up to 7.5. It involves a user mode write access violation triggered by handling a malformed CUR file, leading to potential DoS attacks or code execution.

The Impact of CVE-2021-26237

The exploitation of CVE-2021-26237 could result in a Denial of Service (DoS) condition or enable threat actors to execute arbitrary code on the affected system, posing a significant risk to users' data and system integrity.

Technical Details of CVE-2021-26237

This section delves into the specifics of the CVE-2021-26237 vulnerability, including how it can be exploited and the systems affected.

Vulnerability Description

The vulnerability involves a user mode write access violation in FastStone Image Viewer caused by the mishandling of malformed CUR files by FSViewer.exe. This can be leveraged by attackers for DoS attacks or potentially executing malicious code on the target system.

Affected Systems and Versions

FastStone Image Viewer versions up to 7.5 are impacted by this vulnerability. Users of these versions are at risk of exploitation unless appropriate mitigations are put in place.

Exploitation Mechanism

The CVE-2021-26237 vulnerability can be exploited by tricking a user into opening or viewing a specifically crafted CUR file. When processed by FSViewer.exe, the malformed file triggers the user mode write access violation, leading to potential DoS or code execution scenarios.

Mitigation and Prevention

In this section, we discuss the steps users can take to mitigate the risks associated with CVE-2021-26237 and prevent potential exploitation.

Immediate Steps to Take

Users are advised to update FastStone Image Viewer to a patched version that addresses the vulnerability. Additionally, exercise caution when opening files from untrusted or unknown sources to minimize exposure to potential threats.

Long-Term Security Practices

To enhance overall security posture, users should follow best practices such as keeping software up to date, implementing robust security solutions, and maintaining awareness of the latest threats and vulnerabilities.

Patching and Updates

It is crucial for users to regularly check for updates and apply patches released by FastStone Image Viewer to fix CVE-2021-26237 and other known security issues.