CVE-2020-35592
Pi-hole 5.0, 5.1, and 5.1.1 allows XSS via the Options header to the admin/ URI. A remote user is able to inject arbitrary web script or HTML due to incorrect sanitization of user-supplied data and achieve a Reflected Cross-Site Scripting attack against other users and steal the session cookie.
Date published : 2021-02-18
https://discourse.pi-hole.net/c/announcements/5
https://n4nj0.github.io/advisories/pi-hole-multiple-vulnerabilities-i/