Twig is a template language for PHP. From version 1.0.0 to before version 3.27.0, SecurityPolicy::checkMethodAllowed() unconditionally whitelists all method calls on instances of Twig\Markup. Twig\Markup is not final, so subclasses inherit the bypass.
An application that passes an object of a Markup-derived class into a sandboxed template (typically to mark a chunk of HTML as safe) inadvertently exposes every public method of that subclass to template authors, regardless of the configured allowedMethods list. This issue has been patched in version 3.27.0.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 5
http://github.com/twigphp/Twig/releases/tag/v3.27.0
security-advisories@github.com
https://github.com/twigphp/Twig/security/advisories/GHSA-64jr-qjx4-w2fh
security-advisories@github.com
https://security-tracker.debian.org/tracker/CVE-2026-46636
security-advisories@github.com
https://security-tracker.debian.org/tracker/DSA-6311-1
security-advisories@github.com
https://symfony.com/blog/cve-2026-46636-sandbox-filter-tag-and-function-allow-l…
security-advisories@github.com