CVE-2021-20665 : What You Need to Know

A cross-site scripting vulnerability in Movable Type versions allows remote attackers to inject arbitrary scripts. Learn about the impact, technical details, and mitigation steps.

Understanding CVE-2021-20665

This CVE identifies a cross-site scripting vulnerability in Movable Type, affecting various versions released by Six Apart Ltd.

What is CVE-2021-20665?

The CVE-2021-20665 vulnerability involves the Add asset screen of Contents field in Movable Type, allowing attackers to inject malicious scripts remotely.

The Impact of CVE-2021-20665

This vulnerability can be exploited by remote attackers to execute arbitrary scripts on vulnerable Movable Type versions, potentially leading to unauthorized data access or account hijacking.

Technical Details of CVE-2021-20665

Below are the key technical details related to the CVE-2021-20665 vulnerability.

Vulnerability Description

The vulnerability resides in the Add asset screen of Contents field, enabling remote attackers to inject arbitrary scripts through unspecified vectors.

Affected Systems and Versions

The affected versions include Movable Type 7 r.4705 and earlier from the 7 Series, Movable Type Advanced 7 r.4705 and earlier from the Advanced 7 Series, Movable Type Premium 1.39 and earlier, and Movable Type Premium Advanced 1.39 and earlier.

Exploitation Mechanism

Remote attackers can exploit this vulnerability by injecting malicious scripts into the Add asset screen of the Contents field, potentially compromising the security of the affected Movable Type installations.

Mitigation and Prevention

To address CVE-2021-20665, implement the following mitigation strategies:

Immediate Steps to Take

Update Movable Type to the latest patched version.
Restrict access to vulnerable components.
Implement web application firewalls to filter out malicious inputs.

Long-Term Security Practices

Regularly update Movable Type and all associated plugins.
Conduct security assessments and code reviews regularly.
Educate users about safe browsing practices and security best practices.

Patching and Updates

Refer to the official security advisories and patches released by Six Apart Ltd. for specific guidance on addressing CVE-2021-20665.