In Joomla! before 3.9.19, lack of input validation in the heading tag option of the "Articles - Newsflash" and "Articles - Categories" modules allows XSS.
An issue was discovered in Joomla! before 3.9.17. Incorrect ACL checks in the access level section of com_users allow the unauthorized deletion of usergroups.
An issue was discovered in Joomla! before 3.9.17. Incorrect ACL checks in the access level section of com_users allow the unauthorized editing of usergroups.
An issue was discovered in Joomla! before 3.9.16. Various actions in com_templates lack the required ACL checks, leading to various potential attack vectors.