CVE-2021-41836 Explained : Impact and Mitigation

Fathom Analytics WordPress plugin versions up to and including 3.0.4 are vulnerable to Stored Cross-Site Scripting. This CVE was published on December 8, 2021, impacting multi-site installations.

Understanding CVE-2021-41836

Fathom Analytics <= 3.0.4 Authenticated Stored Cross-Site Scripting

What is CVE-2021-41836?

The Fathom Analytics WordPress plugin is susceptible to Stored Cross-Site Scripting due to inadequate input validation, allowing attackers with admin access to inject malicious scripts.

The Impact of CVE-2021-41836

CVSS Base Score: 4.8 (Medium Severity)
Attack Vector: Network
Privileges Required: High
Scope: Changed
Exploitation may lead to injecting arbitrary web scripts.

Technical Details of CVE-2021-41836

Vulnerability Description

The vulnerability arises from insufficient input validation and escaping through the $site_id parameter in the ~/fathom-analytics.php file.

Affected Systems and Versions

Product: Fathom Analytics
Versions: <= 3.0.4

Exploitation Mechanism

Attackers with administrative user privileges can exploit the vulnerability to insert unauthorized web scripts.

Mitigation and Prevention

Take immediate steps and adopt long-term practices to enhance security.

Immediate Steps to Take

Update to version 3.0.5 or newer.

Long-Term Security Practices

Regularly audit and update plugins.
Enforce strong password policies.

Patching and Updates

Ensure all plugins and software are kept up to date to prevent security vulnerabilities.