Date: 
Wednesday, Aug 7th, 2019
Security risk: 
Moderately Critical
Advisory ID: 
BACKDROP-SA-CORE-2019-011
Vulnerability: 
Cross Site Scripting
Versions affected: 
  • Backdrop Core 1.13.x versions prior to 1.13.3
  • Backdrop Core 1.12.x versions prior to 1.12.8

Backdrop CMS doesn't sufficiently filter output when displaying certain block labels created by administrators. An attacker could potentially craft a specialized label, then have an administrator execute scripting when administering a layout.

This issue is mitigated by the attacker requiring permission to create custom blocks on the site, which is typically an administrative permission.

Solution: 

Upgrade your site to the most recent version of Backdrop core. Download available on the Backdrop CMS 1.13.3 release page. See the update instructions, if needed.

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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  • Check the box labeled "Receive BackdropCMS.org security announcements for core and contrib projects"