Affected versions

Twig versions <=3.26.0 are affected by this security issue.

The issue has been fixed in Twig 3.27.0.

Description

The 3.26.0 source-policy hardening changed the signature of CoreExtension::checkArrow() to take a boolean $isSandboxed instead of an Environment, and added the same $isSandboxed argument to CoreExtension::arraySome() and CoreExtension::arrayEvery(). Compiled templates were updated to pass the per-source sandbox state computed at the call site.

The deprecated internal wrappers exposed in src/Resources/core.php for legacy third-party code (twig_check_arrow_in_sandbox(), twig_array_some(), twig_array_every()) were not updated:

  • twig_array_some() and twig_array_every() call CoreExtension::arraySome() / arrayEvery() without forwarding the sandbox state. The underlying methods default $isSandboxed to false, so the callable-must-be-a-Closure restriction is silently bypassed in sandbox mode and a string callable such as 'strcmp' is accepted.
  • twig_check_arrow_in_sandbox() passes the Environment object where CoreExtension::checkArrow() now expects a bool, which throws a TypeError on PHP 8+.

Compiled Twig templates are not affected: they call CoreExtension::* directly with the correct arguments. Applications are only impacted if they still call the deprecated twig_* helpers on top of a sandboxed Environment.

Resolution

The three wrappers now resolve the current sandbox state via twig_resolve_is_sandboxed() (the same helper compiled templates use), and forward it to the corresponding CoreExtension::* method. twig_check_arrow_in_sandbox() no longer triggers a TypeError, and twig_array_some() / twig_array_every() now enforce the same sandbox restriction as compiled templates.

Credits

We would like to thank El Kharoubi Iosif for reporting the issue and Fabien Potencier for providing the fix.

Published in #Security Advisories #Twig