Vulnerability · Published Mar 24, 2026 · Assigned by GitHub_M
CVE-2026-33157Craft CMS: Potential authenticated Remote Code Execution via malicious attached Behavior
High 8.6
In plain English
A high-severity security flaw in cms from craftcms. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 66% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
Craft CMS is a content management system (CMS). From version 5.6.0 to before version 5.9.13, a Remote Code Execution (RCE) vulnerability exists in Craft CMS, it can be exploited by any authenticated user with control panel access. This is a bypass of a previous fix. The existing patches add cleanseConfig() to assembleLayoutFromPost() and various FieldsController actions to strip Yii2 behavior/event injection keys ("as" and "on" prefixed keys). However, the fieldLayouts parameter in ElementIndexesController::actionFilterHud() is passed directly to FieldLayout::createFromConfig() without any sanitization, enabling the same behavior injection attack chain. This issue has been patched in version 5.9.13.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | craftcms/cms | 5.9.13 | GHSA-2fph-6v5w-89hh |
Affected products (as reported)
Weakness: CWE-470 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/craftcms/cms/security/advisories/GHSA-2fph-6v5w-89hh x_refsource_CONFIRM
- https://github.com/craftcms/cms/commit/97e90b4bdee369c1af3ca77a77531132df240e4e x_refsource_MISC
- https://github.com/craftcms/cms/releases/tag/5.9.13 x_refsource_MISC