Improper revalidation of permissions in Nextcloud Server prior to 14.0.0, 13.0.6 and 12.0.11 lead to not accepting access restrictions by acess tokens.

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.

A bug in Nextcloud Server 15.0.2 causes pending 2FA logins to not be correctly expired when the password of the user is reset.

A missing check in Nextcloud Server 14.0.3 could give recipient the possibility to extend the expiration date of a share they received.

Improper preservation of permissions in Nextcloud Server 14.0.3 causes the event details to be leaked when sharing a non-public event.

Nextcloud Server before 12.0.8 and 13.0.3 suffers from improper checks of dropped permissions for incoming shares allowing a user to still request previews for files it should not have access to.

A bug causing session fixation in Nextcloud Server prior to 14.0.0, 13.0.3 and 12.0.8 could potentially allow an attacker to obtain access to password protected shares.