NextCloud Server and NextCloud Enterprise Server provide file storage for Nextcloud, a self-hosted productivity platform. Starting in version 26.0.0 and prior to version 26.0.2, an attacker could supply a URL that redirects an unsuspecting victim from a legitimate domain to an attacker's site. Nextcloud Server and Nextcloud Enterprise Server 26.0.2 contain a patch for this issue. No known workarounds are available.

Nextcloud Server is a data storage system for Nextcloud, a self-hosted productivity platform. When multiple requests are sent in parallel, all of them were executed even if the amount of faulty requests succeeded the limit by the time the response was sent to the client. This allowed someone to send as many requests the server could handle in parallel to bruteforce protected details instead of the configured limit, default 8. Nextcloud Server versions 25.0.7 and 26.0.2 and Nextcloud Enterprise Server versions 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7 and 26.0.2 contain patches for this issue.

Calendar app for Nextcloud easily sync events from various devices with your Nextcloud. Some internal paths of the website are disclosed when the SMTP server is unavailable. It is recommended that the Calendar app is updated to 3.5.5 or 4.2.3

Contacts app for Nextcloud easily syncs contacts from various devices with your Nextcloud and allows editing. The unsanitized SVG is converted to a JavaScript blob (in memory data) that the Avatar can't render. Due to this constellation the missing sanitization does not seem to be exploitable. It is recommended that the Contacts app is upgraded to 5.0.3 or 4.2.4

Nextcloud Mail is a mail app in Nextcloud. A blind SSRF attack allowed to send GET requests to services running in the same web server. It is recommended that the Mail app is update to version 3.02, 2.2.5 or 1.15.3.

Nextcloud server is an open source personal cloud implementation. Missing brute-force protection on the WebDAV endpoints via the basic auth header allowed to brute-force user credentials when the provided user name was not an email address. Users from version 24.0.0 onward are affected. This issue has been addressed in releases 24.0.11, 25.0.5 and 26.0.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

NextCloud Cookbook is a recipe library app. Prior to commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch, the `pull-checks.yml` workflow is vulnerable to command injection attacks because of using an untrusted `github.head_ref` field. The `github.head_ref` value is an attacker-controlled value. Assigning the value to `zzz";echo${IFS}"hello";#` can lead to command injection. Since the permission is not restricted, the attacker has a write-access to the repository. This issue is fixed in commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch. There is no risk for the user of the app within the NextCloud server. This only affects the main repository and possible forks of it. Those who have forked the NextCloud Cookbook repository should make sure their forks are on the latest version to prevent code injection attacks and similar.

Nextcloud server provides a home for data. A regression in the session handling between Nextcloud Server and the Nextcloud Text app prevented a correct destruction of the session on logout if cookies were not cleared manually. After successfully authenticating with any other account the previous session would be continued and the attacker would be authenticated as the previously logged in user. It is recommended that the Nextcloud Server is upgraded to 25.0.6 or 26.0.1.

user_oidc app is an OpenID Connect user backend for Nextcloud. Authentication can be broken/bypassed in user_oidc app. It is recommended that the Nextcloud user_oidc app is upgraded to 1.3.2

Nextcloud Server is the file server software for Nextcloud, a self-hosted productivity platform. In Nextcloud Server 24.0.0 prior to 24.0.11 and 25.0.0 prior to 25.0.5; as well as Nextcloud Server Enterprise 23.0.0 prior to 23.0.12.6, 24.0.0 prior to 24.0.11, and 25.0.0 prior to 25.0.5; an attacker is not restricted in verifying passwords of share links so they can just start brute forcing the password. Nextcloud Server 24.0.11 and 25.0.5 and Nextcloud Enterprise Server 23.0.12.6, 24.0.11, and 25.0.5 contain a fix for this issue. No known workarounds are available.