Drupal core - Moderately critical - Cross Site Scripting - SA-CORE-2021-011

Project: Drupal core
Date: 2021-November-17
Security risk: Moderately critical 13∕25
Vulnerability: Cross Site Scripting

Description

The Drupal project uses the CKEditor library for WYSIWYG editing. CKEditor has released a security update that impacts Drupal, along with a hotfix for that update.

Vulnerabilities are possible if Drupal is configured to allow use of the CKEditor library for WYSIWYG editing. An attacker that can create or edit content (even without access to CKEditor themselves) may be able to exploit one or more Cross-Site Scripting (XSS) vulnerabilities to target users with access to the WYSIWYG CKEditor, including site admins with privileged access.

For more information, see CKEditor's security advisories:

• CVE-2021-41165: HTML comments vulnerability allowing to execute JavaScript code
• CVE-2021-41164: Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML

Solution

Install the latest version:

If you are using Drupal 9.2, update to Drupal 9.2.9.
If you are using Drupal 9.1, update to Drupal 9.1.14.
If you are using Drupal 8.9, update to Drupal 8.9.20.

Versions of Drupal prior to 9.1.x are end-of-life and do not receive security coverage.

Note that Drupal 8 has reached its end of life so this is the final security release provided for Drupal 8.

Drupal 7 core does not include the CKEditor module and therefore is not affected.