CVE-2021-35489
Thruk 2.40-2 allows /thruk/#cgi-bin/extinfo.cgi?type=2&host={HOSTNAME]&service={SERVICENAME]&backend={BACKEND] Reflected XSS via the host or service parameter. An attacker could inject arbitrary JavaScript into extinfo.cgi. The malicious payload would be triggered every time an authenticated user browses the page containing it.
Source: CVE-2021-35489