CVE-2026-31857

HIGH

CraftCMS has an RCE vulnerability via relational conditionals in the control panel

Published March 11, 2026Updated March 13, 2026Source: osv

Summary

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.

Remediation

Upgrade to the fixed version using your package manager.

Composer

Update craftcms/cms to 4.17.4 or later

composer require "craftcms/cms:^4.17.4"

Composer

Update craftcms/cms to 5.9.9 or later

composer require "craftcms/cms:^5.9.9"

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (2)

Package	Ecosystem	Affected	Fixed In
craftcms/cms	packagist	4.0.0, 4.0.0-RC1, 4.0.0-RC2, 4.0.0-RC3 (+235 more)	4.17.4
craftcms/cms	packagist	5.0.0, 5.0.0-RC1, 5.0.1, 5.0.2 (+152 more)	5.9.9

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CWE-94
Code InjectionMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.8 score means for each attack dimension.

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

—

Confidentiality

—

Integrity

—

Availability

—

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

References

Frequently Asked Questions

What is CVE-2026-31857?: CraftCMS has an RCE vulnerability via relational conditionals in the control panel This vulnerability has been assigned a severity rating of HIGH (CVSS score: 9.8/10).
How do I check if my project is affected by CVE-2026-31857?: CVE-2026-31857 affects craftcms/cms. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-31857 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score

9.8

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-fp5j-j7j4-mcxc

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