April 17, 2019 Fabien Potencier

Affected versions

Symfony 2.7.0 to 2.7.50, 2.8.0 to 2.8.49, 3.4.0 to 3.4.25, 4.1.0 to 4.1.11 and 4.2.0 to 4.2.6 versions of Symfony Framework Bundle templating are affected by this security issue.

The issue has been fixed in Symfony 2.7.51, 2.8.50, 3.4.26, 4.1.12 and 4.2.7.

Note that no fixes are provided for Symfony 3.0, 3.1, 3.2, 3.3, and 4.0 as they are not maintained anymore.

Description

Validation messages were not escaped when using the form theme of the PHP templating engine which, when validation messages may contain user input, could result in an XSS.

Resolution

Ensuring validation form messages are wrapped with $view->escape() .

The patch for this issue is available here for branch 3.4.

Credits

I would like to thank Christophe Coevoet (stof) for reporting & fixing the issue.