The image view functionality in Horde Groupware Webmail Edition before 5.2.22 is affected by a stored Cross-Site Scripting (XSS) vulnerability via an SVG image upload containing a JavaScript payload. An attacker can obtain access to a victim's webmail account by making them visit a malicious URL.
https://lists.horde.org/archives/announce/2020/001290.html
https://lists.debian.org/debian-lts-announce/2020/05/msg00035.html
https://github.com/horde/base/blob/c00f2fdb222055fb2ccb6d53b5b5240c0a7d2a75/docs/CHANGES