In GetSimpleCMS 3.3.15, admin/upload.php blocks .html uploads but Internet Explorer render HTML elements in a .eml file, because of admin/upload-uploadify.php, and validatesafefile in admin/inc/security_functions.php.
{ "versions": [ { "introduced": "0" }, { "last_affected": "3.3.15" } ] }
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-19421.json"