Contao is vulnerable to cross-site scripting in templates
### Impact
It is possible to inject code into the template output that will be executed in the browser in the front end and back end.
### Patches
Update to Contao 4.13.57, 5.3.42 or 5.6.5.
### Workarounds
Do not use the affected templates or patch them manually.
### Refsources
https://contao.org/en/security-advisories/cross-site-scripting-in-templates