An issue was discovered in Joomla! before 3.8.12. Inadequate checks in the InputFilter class could allow specifically prepared phar files to pass the upload filter.
An XSS issue was discovered in the language switcher module in Joomla! 1.6.0 through 3.8.8 before 3.8.9. In some cases, the link of the current language might contain unescaped HTML special characters. This may lead to reflective XSS via injection of arbitrary parameters and/or values on the current page URL.
An issue was discovered in Joomla! 2.5.0 through 3.8.8 before 3.8.9. The autoload code checks classnames to be valid, using the "class_exists" function in PHP. In PHP 5.3, this function validates invalid names as valid, which can result in a Local File Inclusion.
An issue was discovered in com_fields in Joomla! Core before 3.8.8. Inadequate filtering allows users authorised to create custom fields to manipulate the filtering options and inject an unvalidated option.
An issue was discovered in Joomla! Core before 3.8.8. Depending on the server configuration, PHAR files might be handled as executable PHP scripts by the webserver.
An issue was discovered in Joomla! Core before 3.8.8. Inadequate checks allowed users to modify the access levels of user groups with higher permissions.
An issue was discovered in Joomla! Core before 3.8.8. A long running background process, such as remote checks for core or extension updates, could create a race condition where a session that was expected to be destroyed would be recreated.
An issue was discovered in Joomla! Core before 3.8.8. The web install application would autofill password fields after either a form validation error or navigating to a previous install step, and display the plaintext password for the administrator account at the confirmation screen.