Improper Neutralization of Special Elements Used in a Template Engine in Grav CMS - #VU130083
Published: May 5, 2026
Vulnerability identifier: #VU130083
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-1336
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Grav CMS
Affected software:
Grav CMS
Grav CMS
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to improper neutralization of special elements in output used by a downstream component in cleanDangerousTwig() when filtering attacker-controlled Twig templates. A remote user can inject a crafted Twig template that bypasses the blocklist to execute arbitrary code.
The blocklist omits twig_array_reduce and dangerous file functions such as file_get_contents and fwrite.
Remediation
Install security update from vendor's website.