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.

Not strictly enough sanitization in the Nextcloud Android app 3.6.0 allowed an attacker to get content information from protected tables when using custom queries.

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 wrong check for the system time in the Android App 3.9.0 causes a bypass of the lock protection when changing the time of the system to the past.

Missing sanitization in the iOS App 2.24.4 causes an XSS when opening malicious HTML files.

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

Violation of Secure Design Principles in the iOS App 2.23.0 causes the app to leak its login and token to other Nextcloud services when search e.g. for federated users or registering for push notifications.

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 input validator in Nextcloud Server prior to 12.0.3 and 11.0.5 could lead to an attacker's actions not being logged in the audit log.

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.

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.