Creation of folders in read-only folders despite lacking permissions (NC-SA-2017-002)
5th February 2017
Risk level: Low
CVSS v3 Base Score: 4.1 (AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N)
HackerOne report: 169680
Due to a logical error in the file caching layer an authenticated adversary is able to create empty folders inside a shared folder.Note that this only affects folders and files that the adversary has at least read-only permissions for.
- Nextcloud Server < 10.0.2 (CVE-2017-0884)
- Nextcloud Server < 9.0.55 (CVE-2017-0884)
The file cache operation is now only performed if the file system operation succeeded.
It is recommended that all instances are upgraded to Nextcloud 9.0.55 or 10.0.2.
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.