Contao is an open source CMS that allows creation of websites and scalable web applications. In affected versions it is possible to gain privileged rights in the Contao back end. Installations are only affected if they have untrusted back end users who have access to the form generator. All users are advised to update to Contao 4.4.56, 4.9.18 or 4.11.7. As a workaround users may disable the form generator or disable the login for untrusted back end users.
Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS. It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.
Contao before 4.4.52, 4.9.x before 4.9.6, and 4.10.x before 4.10.1 have Improper Input Validation. It is possible to inject insert tags in front end forms which will be replaced when the page is rendered.
Contao 4.8.4 and 4.8.5 has Improper Encoding or Escaping of Output. It is possible to inject insert tags into the login module which will be replaced when the page is rendered.
Contao 4.0 through 4.8.5 allows PHP local file inclusion. A back end user with access to the form generator can upload arbitrary files and execute them on the server.
Contao 4.0 through 4.8.5 has Insecure Permissions. Back end users can manipulate the details view URL to show pages and articles that have not been enabled for them.