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! 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 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. Under specific circumstances (a redirect issued with a URI containing a username and password when the Location: header cannot be used), a lack of escaping the user-info component of the URI could result in an XSS vulnerability.

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. 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.

An issue was discovered in Joomla! Core before 3.8.8. Inadequate input filtering leads to a multiple XSS vulnerabilities. Additionally, the default filtering settings could potentially allow users of the default Administrator user group to perform a XSS attack.

In Joomla! Core before 3.8.8, inadequate filtering of file and folder names leads to various XSS attack vectors in the media manager.

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. Inadequate checks allowed users to see the names of tags that were either unpublished or published with restricted view permission.