Nextcloud Server before 12.0.8 and 13.0.3 suffer from improper authentication on the OAuth2 token endpoint. Missing checks potentially allowed handing out new tokens in case the OAuth2 client was partly compromised.
https://nextcloud.com/security/advisory/?id=nc-sa-2018-003
https://hackerone.com/reports/343111
Source: Mitre, NVD
Published: 2018-07-05
Updated: 2023-02-28
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 8.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Severity: High