An issue was discovered in Joomla! before 3.9.16. Inadequate handling of CSS selectors in the Protostar and Beez3 JavaScript allows XSS attacks.

An issue was discovered in Joomla! before 3.9.16. Missing length checks in the user table can lead to the creation of users with duplicate usernames and/or email addresses.

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.

An issue was discovered in Joomla! before 3.9.15. A missing CSRF token check in the LESS compiler of com_templates causes a CSRF vulnerability.

An issue was discovered in Joomla! before 3.9.15. Missing token checks in the batch actions of various components cause CSRF vulnerabilities.

In Joomla! before 3.9.14, the lack of validation of configuration parameters used in SQL queries caused various SQL injection vectors.

In Joomla! 3.x before 3.9.12, inadequate escaping allowed XSS attacks using the logo parameter of the default templates.

In Joomla! before 3.9.11, inadequate checks in com_contact could allow mail submission in disabled forms.

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 3.9.4. The media form field lacks escaping, leading to XSS.

An issue was discovered in Joomla! before 3.9.4. The item_title layout in edit views lacks escaping, leading to XSS.

An issue was discovered in Joomla! before 3.9.3. Inadequate filtering on URL fields in various core components could lead to an XSS vulnerability.

An issue was discovered in Joomla! before 3.9.3. The phar:// stream wrapper can be used for objection injection attacks because there is no protection mechanism (such as the TYPO3 PHAR stream wrapper) to prevent use of the phar:// handler for non .phar-files.

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.

An issue was discovered in Joomla! before 3.9.3. Inadequate checks at the Global Configuration helpurl settings allowed stored XSS.

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. 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 3.9.2. Inadequate escaping in mod_banners leads to a stored XSS vulnerability.