Nextcloud Server is a space for data storage on Nextcloud, a self-hosted productivity playform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 19.0.0 until 19.0.13.9, 20.0.0 until 20.0.14.14, 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, a user could use this functionality to get access to the login credentials of another user and take over their account. This issue has been patched in Nextcloud Server versions 25.0.7 and 26.0.2 and NextCloud Enterprise Server versions 19.0.13.9, 20.0.14.14, 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2.

Three workarounds are available. Disable app filesexternal. Change config setting "Allow users to mount external storage" to disabled in "Administration" > "External storage" settings …/index.php/settings/admin/externalstorages. Change config setting to disallow users to create external storages in "Administration" > "External storage" settings …/index.php/settings/admin/externalstorages with the types FTP, Nextcloud, SFTP, and/or WebDAV.

NextCloud Server and NextCloud Enterprise Server provide file storage for Nextcloud, a self-hosted productivity platform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, when two server are registered as trusted servers for each other and successfully exchanged the share secrets, the malicious server could modify or delete VCards in the system addressbook on the origin server. This would impact the available and shown information in certain places, such as the user search and avatar menu. If a manipulated user modifies their own data in the personal settings the entry is fixed again.

Nextcloud Server n 25.0.7 and 26.0.2 and Nextcloud Enterprise Server 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2 contain a patch for this issue. A workaround is available. Remove all trusted servers in the "Administration" > "Sharing" settings …/index.php/settings/admin/sharing. Afterwards, trigger a recreation of the local system addressbook with the following occ dav:sync-system-addressbook.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Server and starting in version 20.0.0 and prior to versions 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Enterprise Server, a malicious user could update any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud Server 25.0.13, 26.0.8, and 27.1.3 and Nextcloud Enterprise Server is upgraded to 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 contain a patch for this issue. As a workaround, disable app filesexternal. This workaround also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.

Nextcloud server is an open source personal cloud server. Affected versions were found to be vulnerable to SMTP command injection. The impact varies based on which commands are supported by the backend SMTP server. However, the main risk here is that the attacker can then hijack an already-authenticated SMTP session and run arbitrary SMTP commands as the email user, such as sending emails to other users, changing the FROM user, and so on. As before, this depends on the configuration of the server itself, but newlines should be sanitized to mitigate such arbitrary SMTP command injection. It is recommended that the Nextcloud Server is upgraded to 22.2.8 , 23.0.5 or 24.0.1. There are no known workarounds for this issue.

Nextcloud server is a self hosted home cloud product. In affected versions the OC\Files\Node\Folder::getFullPath() function was validating and normalizing the string in the wrong order. The function is used in the newFile() and newFolder() items, which may allow to creation of paths outside of ones own space and overwriting data from other users with crafted paths. This issue has been addressed in versions 25.0.2, 24.0.8, and 23.0.12. Users are advised to upgrade. There are no known workarounds for this issue.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 20.0.0 and prior to versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a missing password confirmation allowed an attacker, after successfully stealing a session from a logged in user, to create app passwords for the victim. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 19.0.0 and prior to versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a malicious user could delete any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. As a workaround, disable app filesexternal. This also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.

A missing link validation in Nextcloud Server before 20.0.2, 19.0.5, 18.0.11 allows execution of a stored XSS attack using Internet Explorer when saving a 'javascript:' URL in markdown format.

A missing input validation in Nextcloud Server before 20.0.2, 19.0.5, 18.0.11 allows users to store unlimited data in workflow rules causing load and potential DDoS on later interactions and usage with those rules.

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, 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 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, 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, 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, 20.0.11, 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 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. 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 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. 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.

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 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. Nextcloud Server versions prior to 19.0.11, 20.0.10, or 21.0.2 send user IDs to the lookup server even if the user has no fields set to published. The vulnerability is patched in versions 19.0.11, 20.0.10, and 21.0.2; no workarounds outside the updates are known to exist.

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 receive write/read privileges on any Federated File Share. Since public links can be added as federated file share, this can also be exploited on any public link. Users can upgrade to patched versions (19.0.11, 20.0.10 or 21.0.2) or, as a workaround, disable federated file sharing.

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.