An outdated 3rd party library in the Files PDF viewer for Nextcloud Server 18.0.2 caused a Cross-site scripting vulnerability when opening a malicious PDF.
https://nextcloud.com/security/advisory/?id=NC-SA-2020-019
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00019.html
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00040.html
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00038.html
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00037.html