19th July 2016
Risk level: Medium
CVSS v3 Base Score: 3.1 (AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N)
HackerOne report: 145950
The WebDAV endpoint was not properly checking the permission on a WebDAV "COPY" action. This allowed an authenticated attacker with access to a read-only share to put new files in there. It was not possible to modify existing files.
The permission check is now also performed on "COPY" actions,
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory: