25th January 2021
Risk level: Low
CVSS v3 Base Score: 8.7 (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N)
CWE: Improper Access Control - Generic (CWE-284)
HackerOne report: 1061591
A missing user check in Nextcloud 20.0.5 and prior allowed to populate your own credentials for other users external storage configuration when they did not configure one yet.
The error has been fixed.
It is recommended that the Nextcloud Server is upgraded to 20.0.6.
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory: