An issue was discovered in Joomla! before 3.9.6. The debug views of com_users do not properly escape user supplied data, which leads to a potential XSS attack vector.
jQuery before 3.4.0, as used in Drupal, Backdrop CMS, and other products, mishandles jQuery.extend(true, {}, ...) because of Object.prototype pollution. If an unsanitized source object contained an enumerable __proto__ property, it could extend the native Object.prototype.
An issue was discovered in Joomla! before 3.9.5. The Media Manager component does not properly sanitize the folder parameter, allowing attackers to act outside the media manager root directory.
An issue was discovered in Joomla! before 3.9.3. The "No Filtering" textfilter overrides child settings in the Global Configuration. This is intended behavior. However, it might be unexpected for the user because the configuration dialog lacks an additional message to explain this.
An issue was discovered in Joomla! before 3.9.3. Inadequate parameter handling in JavaScript code (core.js writeDynaList) could lead to an XSS attack vector.
An issue was discovered in Joomla! before 3.9.3. A combination of specific web server configurations, in connection with specific file types and browser-side MIME-type sniffing, causes an XSS attack vector.