Nextcloud Groupfolders provides admin-configured folders shared by everyone in a group or team. Prior to 14.0.11, 15.3.12, 16.0.15, 17.0.14, 18.1.8, 19.1.8, and 20.1.2, a user with read-only permission can restore a file from the trash bin. This vulnerability is fixed in 14.0.11, 15.3.12, 16.0.15, 17.0.14, 18.1.8, 19.1.8, and 20.1.2.
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2vrq-fhmf-c49m
https://github.com/nextcloud/groupfolders/pull/4076
https://github.com/nextcloud/groupfolders/issues/4041
https://github.com/nextcloud/groupfolders/commit/bbe87ebed8da23e9df4db637a76fbc8d36439d58