CVE-2026-31857
CraftCMS has an RCE vulnerability via relational conditionals in the control panel
Impact
A Remote Code Execution vulnerability exists in the Craft CMS 5 conditions system. The `BaseElementSelectConditionRule::getElementIds()` method passes user-controlled string input through `renderObjectTemplate()` -- an unsandboxed Twig rendering function with escaping disabled. Any authenticated Control Panel user (including non-admin roles such as Author or Editor) can achieve full RCE by sending a crafted condition rule via standard element listing endpoints. This vulnerability requires no admin privileges, no special permissions beyond basic control panel access, and bypasses all production hardening settings (allowAdminChanges: false, devMode: false, enableTwigSandbox: true). Users should update to the patched 5.99 release to mitigate the issue.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | craftcms/cms | >= 5.0.0-RC1, <= 5.9.8 | 5.9.9 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Craftcms | Craft Cms | from 4.0.0.1 before 4.17.4 from 5.0.1 before 5.9.9 Versions 4.0.0, 5.0.0 |