A Reflected Cross-Site Scripting (XSS) vulnerability in GetSimple CMS v3.3.16, in the admin/index.php login portal webpage, allows remote attackers to execute JavaScript code in the clientβs browser and harvest login credentials after a client clicks a link, enters credentials, and submits the login form.
https://github.com/GetSimpleCMS/GetSimpleCMS/issues/1330
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-23839