Improper Neutralization of Special Elements Used in a Template Engine in Craft CMS - #VU159604
Published: November 6, 2026
Vulnerability identifier: #VU159604
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-1336
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a non-administrator control panel user to execute operating system commands with the PHP worker’s privileges.
The vulnerability exists due to reusable signatures for attacker-controlled Twig returnUrl templates generated by Craft CMS’s app/render-elements endpoint with hyperlink=true in a non-modal context. A non-administrator control panel user can supply a signed template as the login action’s redirect parameter and successfully authenticate, triggering unsandboxed template evaluation and command execution.
Affected software
Craft CMS
Remediation
Install security update from vendor's website.
Craft CMS - update to 5.11.2