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.
In Joomla! before 3.8.4, the lack of type casting of a variable in a SQL statement leads to a SQL injection vulnerability in the Hathor postinstall message.
In Joomla! before 3.8.4, inadequate input filtering in com_fields leads to an XSS vulnerability in multiple field types, i.e., list, radio, and checkbox
The CMS installer in Joomla! before 3.7.4 does not verify a user's ownership of a webspace, which allows remote authenticated users to gain control of the target application by leveraging Certificate Transparency logs.