CVE-2026-55806

Project: Drupal core Date: 2026-June-17 Security risk: Less critical 9 ∕ 25 AC:Basic/A:None/CI:None/II:None/E:Theoretical/TD:Default Vulnerability: Cache poisoning and open redirect Affected versions: <10.5.12 || >=10.6.0 <10.6.11 || >=11.2.0 <11.2.14 || >=11.3.0 <11.3.12 || 11.0.* || 11.1.* CVE IDs: CVE-2026-55806 Description: Drupal core ships a rebuild.php front controller that can be used to rebuild Drupal (clearing the caches and rebuilding the container) when the site is in an unexpected condition. This script doesn't correctly check the Host header against the list of trusted host patterns. This could result in cache poisoning or a redirect to an attacker-controlled domain. Solution: Install the latest version: Drupal 11 If you use Drupal 11.3.x, update to Drupal 11.3.12 . If you use Drupal 11.2.x, update to Drupal 11.2.14 . Drupal 10 If you use Drupal 10.6.x, update to Drupal 10.6.11 . If you use Drupal 10.5.x, update to Drupal 10.5.12 . Drupal 11.1.x, Drupal 11.0.x, Drupal 10.4.x, and below are end-of-life and do not receive security coverage. ( Drupal 8 and Drupal 9 have both reached end-of-life.) Reported By: Melih Acikoz Michael Winser (michaelwinser) Willem Drupal enthousiast (willempje2) Fixed By: Lee Rowlands (larowlan) of the Drupal Security Team Coordinated By: catch (catch) of the Drupal Security Team cilefen (cilefen) of the Drupal Security Team Greg Knaddison (greggles) of the Drupal Security Team Lee Rowlands (larowlan) of the Drupal Security Team Dave Long (longwave) of the Drupal Security Team James Gilliland (neclimdul) of the Drupal Security Team Juraj Nemec (poker10) of the Drupal Security Team Jess (xjm) of the Drupal Security Team

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