CVE-2021-40100 : What You Need to Know

Concrete CMS through version 8.5.5 is affected by a Stored Cross-Site Scripting (XSS) vulnerability in the Conversations component.

Understanding CVE-2021-40100

This CVE details a Stored XSS issue in Concrete CMS Conversations when using the Rich Text Active Conversation Editor.

What is CVE-2021-40100?

Concrete CMS versions up to 8.5.5 are susceptible to a Stored XSS vulnerability in the Conversations feature.

The Impact of CVE-2021-40100

This vulnerability could allow an attacker to execute malicious scripts in the context of a user's session, potentially leading to account takeover, data theft, or further attacks.

Technical Details of CVE-2021-40100

Concrete CMS CVE-2021-40100 vulnerability specifics:

Vulnerability Description

Stored XSS vulnerability in Conversations with Rich Text Editor.

Affected Systems and Versions

Product: Concrete CMS
Versions affected: Up to 8.5.5

Exploitation Mechanism

Attacker injects malicious scripts via the Rich Text Active Conversation Editor.

Mitigation and Prevention

Immediate actions and long-term security measures:

Immediate Steps to Take

Update Concrete CMS to version 8.5.6 or later.
Disable the Rich Text Conversation Editor if not essential.
Regularly monitor for any unauthorized changes or activity.

Long-Term Security Practices

Implement input validation and output encoding to prevent XSS.
Provide security training for users and developers.

Patching and Updates

Stay informed about security patches and updates from Concrete CMS.