Wednesday, Jan 27th, 2021
Security risk: 
Advisory ID: 
Third Party Libraries
Versions affected: 
  • Backdrop Core 1.18.x versions prior to 1.18.1
  • Backdrop Core 1.17.x versions prior to 1.17.6

Backdrop versions 1.16 and prior do not receive security coverage.


The Backdrop project uses the pear Archive_Tar library, which has released a security update that impacts Backdrop. For more information please see:

Exploits may be possible if Backdrop is configured to allow .tar.tar.gz.bz2, or .tlz file uploads and processes them, or if the Installer module is enabled.


Upgrade your site to the most recent version of Backdrop core. Download available on the Backdrop CMS 1.18.1 release page. See the update instructions, if needed.

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"