Thursday, Nov 18th, 2021
Advisory ID: 
Security risk: 
Moderately Critical
  • Cross Site Scripting
  • Third Party Libraries
Versions affected: 
  • Backdrop Core 1.20.x versions prior to 1.20.2
  • Backdrop Core 1.19.x versions prior to 1.19.5

Backdrop versions 1.18 and prior do not receive security coverage.


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

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

For more information, see CKEditor's security advisories.


Upgrade your site to the most recent version of Backdrop core. Download available on the Backdrop CMS 1.20.2 release page. See the update instructions, if needed.

Reported By: 
  • Jacek Bogdański coordinated on the release with Drupal project.
  • See the CKEditor announcements above for the original reporters of the vulnerabilities.
Fixed By: 

Security email list

Backdrop maintains a security mailing list. Whenever a security release comes out, an email will be sent to everyone subscribed to that list, announcing the new release. Please follow the steps below to join the Security email list.

  • Log in to
  • Edit your profile
  • Scroll down to the "Email notifications" section
  • Check the box labeled "Receive security announcements for core and contrib projects"