Drupal core - Moderately critical - Gadget chain - SA-CORE-2026-006

Project: Drupal core Date: 2026-June-17 Security risk: Moderately critical 14 ∕ 25 AC:Complex/A:Admin/CI:All/II:All/E:Theoretical/TD:Uncommon Vulnerability: Gadget chain 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-2026-55804 Description: Drupal core contains a chain of methods that could be exploitable when an insecure deserialization vulnerability exists on the site. This so-called "gadget chain" presents no direct threat, but is a vector that can be used to achieve remote code execution or SQL injection if the application deserializes untrusted data due to another vulnerability. This issue is not directly exploitable. This issue is mitigated by the fact that in order for it to be exploitable, a separate vulnerability must be present to allow an attacker to pass unsafe input to unserialize() . 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: Michael Maturi (michaelmaturi) Fixed By: Lee Rowlands (larowlan) of the Drupal Security Team Drew Webber (mcdruid) of the Drupal Security Team Mohit Aghera (mohit_aghera) Coordinated By: Anna Kalata (akalata) of the Drupal Security Team Benji Fisher (benjifisher) 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 Drew Webber (mcdruid) of the Drupal Security Team Juraj Nemec (poker10) of the Drupal Security Team Jess (xjm) of the Drupal Security Team