Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure and add new files.​ This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.6.5, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure, and add new files.​ Users should upgrade the Nextcloud Desktop client to 3.6.5 to receive a patch. No known workarounds are available.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.6.5, a malicious server administrator can recover and modify the contents of end-to-end encrypted files. Users should upgrade the Nextcloud Desktop client to 3.6.5 to receive a patch. No known workarounds are available.

user_oidc is the OIDC connect user backend for Nextcloud, an open source collaboration platform. A vulnerability in versions 1.0.0 until 1.3.0 effectively allowed an attacker to bypass the state protection as they could just copy the expected state token from the first request to their second request. Users should upgrade user_oidc to 1.3.0 to receive a patch for the issue. No known workarounds are available.

Nextcloud Server is an open source personal cloud server. Nextcloud Server 24.0.0 until 24.0.6 and 25.0.0 until 25.0.4, as well as Nextcloud Enterprise Server 23.0.0 until 23.0.11, 24.0.0 until 24.0.6, and 25.0.0 until 25.0.4, have an information disclosure vulnerability. A user was able to get the full data directory path of the Nextcloud server from an API endpoint. By itself this information is not problematic as it can also be guessed for most common setups, but it could speed up other unknown attacks in the future if the information is known. Nextcloud Server 24.0.6 and 25.0.4 and Nextcloud Enterprise Server 23.0.11, 24.0.6, and 25.0.4 contain patches for this issue. There are no known workarounds.

Nextcloud talk is a video & audio conferencing app for Nextcloud. In affected versions the talk app does not properly filter access to a conversations member list. As a result an attacker could use this vulnerability to gain information about the members of a Talk conversation, even if they themselves are not members. It is recommended that the Nextcloud Talk is upgraded to 14.0.9 or 15.0.4. There are no known workarounds for this vulnerability.

Nextcloud server is an open source home cloud implementation. In affected versions users that should not be able to download a file can still download an older version and use that for uncontrolled distribution. This issue has been addressed in versions 24.0.10 and 25.0.4. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Nextcloud richdocuments is a Nextcloud app integrating the office suit Collabora Online. In affected versions the secure view feature of the rich documents app can be bypassed by using unprotected internal API endpoint of the rich documents app. It is recommended that the Nextcloud Office app (richdocuments) is upgraded to 8.0.0-beta.1, 7.0.2 or 6.3.2. Users unable to upgrade may mitigate the issue by taking steps to restrict the ability to download documents. This includes ensuring that the `WOPI configuration` is configured to only serve documents between Nextcloud and Collabora. It is highly recommended to define the list of Collabora server IPs as the allow list within the Office admin settings of Nextcloud.

Nextcloud server is an open source home cloud implementation. In affected versions the generated fallback password when creating a share was using a weak complexity random number generator, so when the sharer did not change it the password could be guessable to an attacker willing to brute force it. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. This issue only affects users who do not have a password policy enabled, so enabling a password policy is an effective mitigation for users unable to upgrade.

Nextcloud server is an open source home cloud implementation. In affected versions admins of a server were able to upload a logo or a favicon and to provided a file name which was not restricted and could overwrite files in the appdata directory. Administrators may have access to overwrite these files by other means but this method could be exploited by tricking an admin into uploading a maliciously named file. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should avoid ingesting logo files from untrusted sources.