Nextcloud Server — набор клиент-серверных программ для создания и использования хранилища данных.

Nextcloud Server before 9.0.58 and 10.0.5 and 11.0.3 are vulnerable to an inadequate escaping of error messages leading to XSS vulnerabilities in multiple components.

Nextcloud Server before 11.0.3 is vulnerable to an inadequate escaping leading to a XSS vulnerability in the search module. To be exploitable a user has to write or paste malicious content into the search dialogue.

Nextcloud Server before 11.0.3 is vulnerable to an improper session handling allowed an application specific password without permission to the files access to the users file.

Nextcloud Server before 9.0.58 and 10.0.5 and 11.0.3 are shipping a vulnerable JavaScript library for sanitizing untrusted user-input which suffered from a XSS vulnerability caused by a behaviour change in Safari 10.1 and 10.2. Note that Nextcloud employs a strict Content-Security-Policy preventing exploitation of this XSS issue on modern web browsers.

Nextcloud Server before 11.0.7 and 12.0.5 suffers from an Authorization Bypass Through User-Controlled Key vulnerability. A missing ownership check allowed logged-in users to change the scope of app passwords of other users. Note that the app passwords themselves where neither disclosed nor could the error be misused to identify as another user.

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

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.

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.

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.

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.