CVE-2026-31857: craftcms cms Code Injection

Vulnerability summary

CVE-2026-31857 is a high (CVSS 8.8) Code Injection vulnerability in craftcms cms. EPSS estimates a 0.92% chance of exploitation in the next 30 days, higher than 59.6% of scored vulnerabilities.

Timeline

1. 11-03-2026
   PublishedVulnerability first disclosed.
2. 12-03-2026
   Last modifiedVulnerability information updated.

Description

Craft is a content management system (CMS). Prior to 5.9.9 and 4.17.4, 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 5.9.9 or 4.17.4 release to mitigate the issue.

• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.