3rd October 2020
Risk level: Low
CVSS v3 Base Score: 5.3 (AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N)
CWE: Insufficiently Protected Credentials (CWE-522)
HackerOne report: 743505
Insufficient protection of the server-side encryption keys in Nextcloud Server 19.0.1 allowed an attacker to replace the public key to decrypt them later on.
The error has been fixed.
It is recommended that the Nextcloud Server is upgraded to 20.0.0.
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory: