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

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying restore privileges when restoring a file. The restore capability of Nextcloud/ownCloud was not verifying whether a user has only read-only access to a share. Thus a user with read-only access was able to restore old versions.

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not ...

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying edit check permissions on WebDAV copy actions. The WebDAV endpoint was not properly checking the permission on a WebDAV COPY action. This allowed an authenticated attacker with access to a read-only share to put new files in there. It was not possible to modify existing files.

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not ...

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are vulnerable to a log pollution vulnerability potentially leading to a local XSS. The download log functionality in the admin screen is delivering the log in JSON format to the end-user. The file was delivered with an attachment disposition forcing the browser to download the document. However, Firefox running on Microsoft Windows would offer the user to open the data in the browser as an HTML document. Thus any injected data in the log would be executed.

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are vuln ...

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying edit check permissions on WebDAV copy actions. The WebDAV endpoint was not properly checking the permission on a WebDAV COPY action. This allowed an authenticated attacker with access to a read-only share to put new files in there. It was not possible to modify existing files.

Nextcloud Server before 9.0.54 and 10.0.0 suffers from an improper authorization check on removing shares. The Sharing Backend as implemented in Nextcloud does differentiate between shares to users and groups. In case of a received group share, users should be able to unshare the file to themselves but not to the whole group. The previous API implementation simply unshared the file to all users in the group.

Nextcloud Server before 10.0.1 & ownCloud Server before 9.0.6 and 9.1.2 suffer from Reflected XSS in the Gallery application. The gallery app was not properly sanitizing exception messages from the Nextcloud/ownCloud server. Due to an endpoint where an attacker could influence the error message, this led to a reflected Cross-Site-Scripting vulnerability.

Nextcloud Server before 9.0.52 & ownCloud Server before 9.0.4 are not properly verifying restore privileges when restoring a file. The restore capability of Nextcloud/ownCloud was not verifying whether a user has only read-only access to a share. Thus a user with read-only access was able to restore old versions.