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

CVE-2026-31857 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

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.

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-03-11 14:56:45 UTC
Updated
2026-03-11 20:44:42 UTC
GitHub reviewed
2026-03-11 14:56:45 UTC
NVD published
2026-03-11

EPSS Score

Score Percentile
0.12% 30.79%

CVSS Scores

Base score Version Severity Vector
8.1 4.0 —
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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:U)
Unreported: no public PoC, no reported exploitation, and no known simplification tools.

Identifiers

Type Value
GHSA GHSA-fp5j-j7j4-mcxc ↗
CVE CVE-2026-31857 ↗

CWEs

CWE id Name
CWE-94 Improper Control of Generation of Code ('Code Injection')

Credits

  • Neosprings (reporter)

Affected packages (2)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer craftcms/cms >= 5.0.0-RC1, <= 5.9.8 5.9.9 —
composer craftcms/cms >= 4.0.0-beta.1, <= 4.17.3 4.17.4 —

References

cvelogic Threat Intelligence