An authenticated server-side request forgery in Nextcloud server 16.0.1 allowed to detect local and remote services when adding a new subscription in the calendar application.

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

Improper Input Validation in Nextcloud Server 15.0.7 allows group admins to create users with IDs of system folders.

Exposure of Private Information in Nextcloud Server 16.0.1 causes the server to send it's domain and user IDs to the Nextcloud Lookup Server without any further data when the Lookup server is disabled.

Improper permissions preservation in Nextcloud Server 16.0.1 causes sharees to be able to reshare with write permissions when sharing the mount point of a share they received, as a public link.

Improper neutralization of file names, conversation names and board names in Nextcloud Server 16.0.3, Nextcloud Talk 6.0.3 and Nextcloud Deck 0.6.5 causes an XSS when linking them with each others in a project.

Missing escaping of HTML in the Updater of Nextcloud 15.0.5 allowed a reflected XSS when starting the updater from a malicious location.

A missing check in Nextcloud Server 17.0.0 allowed an attacker to set up a new second factor when trying to login.

Dangling remote share attempts in Nextcloud 16 allow a DNS pollution when running long.

A bug in Nextcloud Server 17.0.1 causes the workflow rules to depend their behaviour on the file extension when checking file mimetypes.

A missing check in the Nextcloud Server prior to version 15.0.1 causes leaking of calendar event names when adding or modifying confidential or private events.

A missing check in Nextcloud Server prior to 14.0.0 could give unauthorized access to the previews of single file password protected shares.

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.

Missing state in Nextcloud Server prior to 14.0.0 would not enforce the use of a second factor at login if the the provider of the second factor failed to load.

A missing access check in Nextcloud Server prior to 14.0.0 could lead to continued access to password protected link shares when the owner had changed the password.

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.

A missing sanitization of search results for an autocomplete field in NextCloud Server <13.0.5 could lead to a stored XSS requiring user-interaction. The missing sanitization only affected user names, hence malicious search results could only be crafted by authenticated users.

Improper Authentication in Nextcloud Server prior to version 12.0.3 would allow an attacker that obtained user credentials to bypass the 2 Factor Authentication.

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.

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.