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.
{
"cpes": [
"cpe:2.3:a:joomla:joomla!:*:*:*:*:*:*:*:*"
],
"severity": "Medium"
}