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 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. 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 3.9.2. Inadequate checks of the Global Configuration helpurl settings allowed stored XSS.

An issue was discovered in Joomla! before 3.9.2. Inadequate escaping in mod_banners leads to a stored XSS vulnerability.

An issue was discovered in Joomla! before 3.9.2. Inadequate escaping in com_contact leads to a stored XSS vulnerability.

An issue was discovered in Joomla! before 3.9.2. Inadequate checks of the Global Configuration Text Filter settings allowed stored XSS.

An issue was discovered in Joomla! before 3.8.13. com_joomlaupdate allows the execution of arbitrary code. The default ACL config enabled the ability of Administrator-level users to access com_joomlaupdate and trigger code execution.