CVE-2021-21340 : What You Need to Know

TYPO3 is an open-source PHP-based web content management system. This vulnerability, identified as CVE-2021-21340, affects versions before 10.4.14 and 11.1.1. An attacker can exploit this vulnerability to execute cross-site scripting attacks when previewing database fields designated as descriptionColumn. A valid backend user account is required to exploit this vulnerability. TYPO3 has released patches in versions 10.4.14 and 11.1.1 to address this issue.

Understanding CVE-2021-21340

This section delves into the specifics of the CVE-2021-21340 vulnerability.

What is CVE-2021-21340?

CVE-2021-21340 is a cross-site scripting vulnerability in TYPO3 CMS versions prior to 10.4.14 and 11.1.1. It allows malicious actors to execute scripts in the context of an authenticated user's session, potentially leading to unauthorized actions.

The Impact of CVE-2021-21340

The impact of this vulnerability includes the potential for unauthorized access, data manipulation, and exposure of sensitive information.

Technical Details of CVE-2021-21340

In this section, we discuss the technical aspects of the CVE-2021-21340 vulnerability.

Vulnerability Description

The vulnerability arises from inadequate sanitization of database fields used as descriptionColumn, enabling the injection of malicious scripts.

Affected Systems and Versions

TYPO3 CMS versions before 10.4.14 and 11.1.1 are impacted by this vulnerability.

Exploitation Mechanism

To exploit CVE-2021-21340, an attacker needs a valid backend user account to insert malicious scripts into the descriptionColumn fields.

Mitigation and Prevention

Here we outline steps to mitigate and prevent the exploitation of CVE-2021-21340.

Immediate Steps to Take

Users should update their TYPO3 installations to versions 10.4.14 or 11.1.1 to eliminate this vulnerability. It is crucial to ensure that all backend users have strong, unique passwords to prevent unauthorized access.

Long-Term Security Practices

Implement secure coding practices by validating and sanitizing user input to mitigate cross-site scripting vulnerabilities. Regularly monitor security advisories and apply patches promptly.

Patching and Updates

Stay informed about security updates from TYPO3 and promptly apply patches to ensure the protection of your systems.