CVE-2026-33157 Craft CMS: Potential authenticated Remote Code Execution via malicious attached Behavior
Authenticated users can execute arbitrary code via unsanitized field layout parameters in Craft CMS control panel.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33157?
CVE-2026-33157 is a high-severity code injection vulnerability in Craftcms Craft Cms, published on 24 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
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.
Weakness: CWE-470
Which versions are affected by CVE-2026-33157?
2 open source packages ship an affected version, including craftcms/cms. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
craftcms/cms Packagist | From 5.6.0 | 5.9.13 |
craftcms/cms Packagist | From 5.6.0 | 5.9.13 |
Products include Craftcms Craft Cms.
How do I fix CVE-2026-33157?
Upgrade craftcms/cms to 5.9.13 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-33157 being exploited?
There is no known exploitation of CVE-2026-33157 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Craftcms Craft Cms
Sources
Also known as CLSA-2026-1790174106, GHSA-2fph-6v5w-89hh.