Twig security release: Possibility to load a template outside a configured directory when using the filesystem loader

Affected versions

Twig >1.0.0,<1.44.7 || >2.0.0,<2.15.3 || >3.0.0,<3.4.3 are affected by this security issue.

The issue has been fixed in Twig 1.44.7, 2.15.3 and 3.4.3.

Description

When using the filesystem loader to load templates for which the name is a user input, it is possible to use the source or include statement to read arbitrary files from outside the templates directory when using a namespace like @somewhere/../some.file (in such a case, validation is bypassed).

Resolution

We fixed validation for such template names.

Even if the 1.x branch is not maintained anymore, a new version has been released.

Credits

We would like to thank Dariusz Tytko for reporting the issue and Fabien Potencier for fixing the issue.