In Horde Groupware 5.2.19 and 5.2.21, there is XSS via the Color field in a Create Task List action.
https://lists.debian.org/debian-lts-announce/2020/08/msg00047.html
https://lists.debian.org/debian-lts-announce/2020/08/msg00046.html
https://github.com/horde/base/commit/fb2113bbcd04bd4a28c46aad0889fb0a3979a230
https://euvd.enisa.europa.eu/vulnerability/EUVD-2017-8077
http://code610.blogspot.com/2017/11/rce-via-xss-horde-5219.html