Nextcloud is an open-source, self-hosted productivity platform. Prior to versions 20.0.13, 21.0.5, and 22.2.0, Nextcloud Server did not implement a database backend for rate-limiting purposes. Any component of Nextcloud using rate-limits (as as `AnonRateThrottle` or `UserRateThrottle`) was thus not rate limited on instances not having a memory cache backend configured. In the case of a default installation, this would notably include the rate-limits on the two factor codes. It is recommended that the Nextcloud Server be upgraded to 20.0.13, 21.0.5, or 22.2.0. As a workaround, enable a memory cache backend in `config.php`.

Nextcloud server is an open source, self hosted personal cloud. Nextcloud supports rendering image previews for user provided file content. For some image types, the Nextcloud server was invoking a third-party library that wasn't suited for untrusted user-supplied content. There are several security concerns with passing user-generated content to this library, such as Server-Side-Request-Forgery, file disclosure or potentially executing code on the system. The risk depends on your system configuration and the installed library version. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. These versions do not use this library anymore. As a workaround users may disable previews by setting `enable_previews` to `false` in `config.php`.

Nextcloud server is an open source, self hosted personal cloud. In affected versions logging of exceptions may have resulted in logging potentially sensitive key material for the Nextcloud Encryption-at-Rest functionality. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. If upgrading is not an option users are advised to disable system logging to resolve this issue until such time that an upgrade can be performed Note that ff you do not use the Encryption-at-Rest functionality of Nextcloud you are not affected by this bug.

Nextcloud server is an open source, self hosted personal cloud. In affected versions an attacker is able to bypass Two Factor Authentication in Nextcloud. Thus knowledge of a password, or access to a WebAuthN trusted device of a user was sufficient to gain access to an account. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.1.0. There are no workaround for this vulnerability.

Nextcloud Text is an open source plaintext editing application which ships with the nextcloud server. In affected versions the Nextcloud Text application returned different error messages depending on whether a folder existed in a public link share. This is problematic in case the public link share has been created with "Upload Only" privileges. (aka "File Drop"). A link share recipient is not expected to see which folders or files exist in a "File Drop" share. Using this vulnerability an attacker is able to enumerate folders in such a share. Exploitation requires that the attacker has access to a valid affected "File Drop" link share. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.0.1. Users who are unable to upgrade are advised to disable the Nextcloud Text application in the app settings.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, there was a lack of ratelimiting on the public share link mount endpoint. This may have allowed an attacker to enumerate potentially valid share tokens. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, the Nextcloud Text application shipped with Nextcloud Server returned verbatim exception messages to the user. This could result in a full path disclosure on shared files. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. As a workaround, one may disable the Nextcloud Text application in Nextcloud Server app settings.

Nextcloud Text is a collaborative document editing application that uses Markdown. A cross-site scripting vulnerability is present in versions prior to 19.0.13, 20.0.11, and 21.0.3. The Nextcloud Text application shipped with Nextcloud server used a `text/html` Content-Type when serving files to users. Due the strict Content-Security-Policy shipped with Nextcloud, this issue is not exploitable on modern browsers supporting Content-Security-Policy. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. As a workaround, use a browser that has support for Content-Security-Policy.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, default share permissions were not being respected for federated reshares of files and folders. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, there was a lack of ratelimiting on the public DAV endpoint. This may have allowed an attacker to enumerate potentially valid share tokens or credentials. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, there was a lack of ratelimiting on the shareinfo endpoint. This may have allowed an attacker to enumerate potentially valid share tokens. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server supports application specific tokens for authentication purposes. These tokens are supposed to be granted to a specific applications (e.g. DAV sync clients), and can also be configured by the user to not have any filesystem access. Due to a lacking permission check, the tokens were able to change their own permissions in versions prior to 19.0.13, 20.0.11, and 21.0.3. Thus fileystem limited tokens were able to grant themselves access to the filesystem. The issue is patched in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds aside from upgrading.

Nextcloud Server is a Nextcloud package that handles data storage. In versions priot to 19.0.13, 20.0.11, and 21.0.3, Nextcloud Server audit logging functionality wasn't properly logging events for the unsetting of a share expiration date. This event is supposed to be logged. This issue is patched in versions 19.0.13, 20.0.11, and 21.0.3.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.0.11, and 21.0.3, filenames where not escaped by default in controllers using `DownloadResponse`. When a user-supplied filename was passed unsanitized into a `DownloadResponse`, this could be used to trick users into downloading malicious files with a benign file extension. This would show in UI behaviours where Nextcloud applications would display a benign file extension (e.g. JPEG), but the file will actually be downloaded with an executable file extension. The vulnerability is patched in versions 19.0.13, 20.0.11, and 21.0.3. Administrators of Nextcloud instances do not have a workaround available, but developers of Nextcloud apps may manually escape the file name before passing it into `DownloadResponse`.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.0.11, and 21.0.3, ratelimits are not applied to OCS API responses. This affects any OCS API controller (`OCSController`) using the `@BruteForceProtection` annotation. Risk depends on the installed applications on the Nextcloud Server, but could range from bypassing authentication ratelimits or spamming other Nextcloud users. The vulnerability is patched in versions 19.0.13, 20.0.11, and 21.0.3. No workarounds aside from upgrading are known to exist.

Nextcloud server before 19.0.11, 20.0.10, 21.0.2 is vulnerable to brute force attacks due to lack of inclusion of IPv6 subnets in rate-limiting considerations. This could potentially result in an attacker bypassing rate-limit controls such as the Nextcloud brute-force protection.

Nextcloud Server is a Nextcloud package that handles data storage. In versions of Nextcloud Server prior to 10.0.11, 20.0.10, and 21.0.2, a malicious user may be able to break the user administration page. This would disallow administrators to administrate users on the Nextcloud instance. The vulnerability is fixed in versions 19.0.11, 20.0.10, and 21.0.2. As a workaround, administrators can use the OCC command line tool to administrate the Nextcloud users.

Nextcloud Server is a Nextcloud package that handles data storage. A vulnerability in federated share exists in versions prior to 19.0.11, 20.0.10, and 21.0.2. An attacker can gain access to basic information about users of a server by accessing a public link that a legitimate server user added as a federated share. This happens because Nextcloud supports sharing registered users with other Nextcloud servers, which can be done automatically when selecting the "Add server automatically once a federated share was created successfully" setting. The vulnerability is patched in versions 19.0.11, 20.0.10, and 21.0.2 As a workaround, disable "Add server automatically once a federated share was created successfully" in the Nextcloud settings.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.11, 20.0.10, and 21.0.2, an attacker is able to convert a Files Drop link to a federated share. This causes an issue on the UI side of the sharing user. When the sharing user opens the sharing panel and tries to remove the "Create" privileges of this unexpected share, Nextcloud server would silently grant the share read privileges. The vulnerability is patched in versions 19.0.11, 20.0.10 and 21.0.2. No workarounds are known to exist.