Date: 
Wednesday, Jan 8th, 2025
Advisory ID: 
BACKDROP-SA-CORE-2025-001
Security risk: 
Moderately Critical
Vulnerability: 
Cross Site Scripting
Versions affected: 
  • Backdrop Core 1.29.x versions prior to 1.29.3
  • Backdrop Core 1.28.x versions prior to 1.28.5

Backdrop versions 1.27 and prior do not receive security coverage.

Description: 

Backdrop CMS doesn't sufficiently isolate long text content when the CKEditor 5 rich text editor is used. This allows a potential attacker to craft specialized HTML and JavaScript that may be executed when an administrator attempts to edit a piece of content.

This vulnerability is mitigated by the fact that an attacker must have the ability to create long text content (such as through the node or comment forms) and an administrator must edit (not view) the content that contains the malicious content. This problem only exists when using the CKEditor 5 module.

A CVE has been requested, and this page will be updated as soon as an official number has been issued.

Solution: 

Upgrade your site to the most recent version of Backdrop core. Download available on the Backdrop CMS 1.29.3 release page. See the update instructions, if needed.

Reported By: 
Fixed By: 
Coordinated 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.

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  3. Switch to the "Subscriptions" tab
  4. Check the box labeled "Security updates"
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