Edit permission check not enforced on WebDAV COPY action (NC-SA-2016-004)
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)
CWE: Permission Issues (CWE-275)
HackerOne report: 145950
Description
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.
Affected Software
- Nextcloud Server < 9.0.52 (CVE-2016-9461)
Action Taken
The permission check is now also performed on "COPY" actions,
Resolution
It is recommended that all instances are upgraded to Nextcloud 9.0.52.
Acknowledgements
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:
This advisory is licensed CC BY-SA 4.0.