In some situations, the Image module does not correctly check access to image files not stored in the standard public files directory when generating derivative images using the image styles system.
Access to a non-public file is checked only if it is stored in the “private” file system. However, some contributed modules provide additional file systems, or schemes, which may lead to this vulnerability.
This vulnerability is mitigated by the fact that it only applies when the site sets (Drupal 9) $config[‘image.settings’][‘allow_insecure_derivatives’] or (Drupal 7) $conf[‘image_allow_insecure_derivatives’] to TRUE. The recommended and default setting is FALSE, and Drupal core does not provide a way to change that in the admin UI.
Some sites may require configuration changes following this security release. Review the release notes for your Drupal version if you have issues accessing files or image styles after updating.
Install the latest version:
If you are using Drupal 9.4, update to Drupal 9.4.3.
If you are using Drupal 9.3, update to Drupal 9.3.19.
If you are using Drupal 7, update to Drupal 7.91.
All versions of Drupal 9 prior to 9.3.x are end-of-life and do not receive security coverage. Note that Drupal 8 has reached its end of life.
Conrad Lara
mondrake
Alex Bronstein of the Drupal Security Team
Dave Reid of the Drupal Security Team
xjm of the Drupal Security Team
Guy Elsmore-Paddock
Dave Long Provisional Member of the Drupal Security Team
Lauri Eskola Provisional Member of the Drupal Security Team
David Strauss of the Drupal Security Team
Benji Fisher Provisional Member of the Drupal Security Team
Alex Pott of the Drupal Security Team
Drew Webber of the Drupal Security Team
Fabian Franz