Drupal Core Gadget Chain Disclosure (CVE-2026-6366) Patched Across Supported Branches
Drupal has released security updates to fix a gadget chain vulnerability, CVE-2026-6366, that could enable remote code execution or SQL injection when combined with an insecure deserialization flaw.
The Drupal Security Team has published an advisory for a moderately critical vulnerability in Drupal core, CVE-2026-6366, describing a gadget chain that could be leveraged for remote code execution or SQL injection. The flaw affects versions 8.0.0 through 11.3.6 and is present across all currently supported branches, as well as several end-of-life versions.
The vulnerability is not directly exploitable on its own. According to the advisory, the gadget chain is a collection of methods within Drupal core that, when combined with a separate insecure deserialization vulnerability, could allow an attacker to execute arbitrary code or inject malicious SQL queries. The advisory explicitly notes that no such deserialization flaw is known to exist in Drupal core, meaning the gadget chain currently presents a theoretical risk rather than an active exploit vector.
The Drupal Security Team has released patches in versions 10.5.9, 10.6.7, 11.2.11, and 11.3.7. Administrators running any supported branch are strongly advised to update immediately. Drupal 11.1.x, 11.0.x, 10.4.x, and earlier versions have reached end-of-life and will not receive security coverage, leaving sites on those branches vulnerable if a deserialization attack vector is later discovered in core or contributed modules.
CVE-2026-6366 was reported by Truong Le (hswww), menon, and t-chen. The fix was coordinated and implemented by multiple members of the Drupal Security Team, including Benji Fisher, Neil Drumm, Greg Knaddison, Lee Rowlands, Dave Long, Drew Webber, Ra Mänd, Jess (xjm), and Juraj Nemec.
Gadget chain vulnerabilities have become an increasingly important part of the security landscape, particularly in PHP applications where unserialize() functions are used. While this specific issue is rated moderately critical with a theoretical exploit complexity, the disclosure underscores the importance of defense-in-depth and keeping Drupal core up to date, as gadget chains can dramatically escalate the impact of otherwise low-severity deserialization bugs.
Site owners should audit their environments for any custom modules or contributed projects that may unserialize user-supplied data, and apply the latest Drupal core patches without delay.