Nextcloud Android Client Forces Logout for Profile Takeover

An issue in Nextcloud versionCode 30390190 allows attackers to force victim users to logout of their accounts and switch to an attacker controlled progile, bypassing authentication.

Nextcloud Server User password is available in memory of the PHP process

Nextcloud Server is a self hosted personal cloud system. Under certain conditions the password of a user was stored unencrypted in the session data. The session data is encrypted before being saved in the session storage (Redis or disk), but it would allow a malicious process that gains access to the memory of the PHP process, to get access to the cleartext password of the user. It is recommended that the Nextcloud Server is upgraded to 28.0.12, 29.0.9 or 30.0.2.

Nextcloud Server's Attachments folder for Text app is accessible on "Files drop" and "Password protected" shares

Nextcloud Server is a self hosted personal cloud system. After receiving a "Files drop" or "Password protected" share link a malicious user was able to download attachments that are referenced in Text files without providing the password. It is recommended that the Nextcloud Server is upgraded to 28.0.11, 29.0.8 or 30.0.1 and Nextcloud Enterprise Server is upgraded to 25.0.13.13, 26.0.13.9, 27.1.11.9, 28.0.11, 29.0.8 or 30.0.1.

OAuth2 authorization codes are valid indefinetly in Nextcloud server

Nextcloud server is a self hosted personal cloud system. In affected versions OAuth codes did not expire. When an attacker would get access to an authorization code they could authenticate at any time using the code. As of version 28.0.0 OAuth codes are invalidated after 10 minutes and will no longer be authenticated. To exploit this vulnerability an attacker would need to intercept an OAuth code from a user session. It is recommended that the Nextcloud Server is upgraded to 28.0.0. There are no known workarounds for this vulnerability.

Nextcloud Server's disabled download shares still allow download through preview images

Nextcloud Server is an open source personal cloud server. Prior to versions 24.0.7 and 25.0.1, disabled download shares still allow download through preview images. Images could be downloaded and previews of documents (first page) can be downloaded without being watermarked. Versions 24.0.7 and 25.0.1 contain a fix for this issue. No known workarounds are available.

Nextcloud Server has no password length limit when creating a user as an administrator

Nextcloud Server is an open source personal cloud server. Prior to versions 23.0.11, 24.0.7, and 25.0.0, there is no password length limit when creating a user as an administrator. An administrator can cause a limited DoS attack against their own server. Versions 23.0.11, 24.0.7, and 25.0.0 contain a fix for the issue. As a workaround, don't create user accounts with long passwords.

Nextcloud Server's calendar name length not validated before writing to database

Nextcloud Server is an open source personal cloud server. Prior to versions 23.0.10 and 24.0.5, calendar name lengths are not validated before writing to a database. As a result, an attacker can send unnecessary amounts of data against the database. Version 23.0.10 and 24.0.5 contain patches for the issue. No known workarounds are available.

Database resource exhaustion for logged-in users via sharee recommendations with circles

Nextcloud Server is the file server software for Nextcloud, a self-hosted productivity platform. Nextcloud Server prior to versions 23.0.10 and 24.0.6 and Nextcloud Enterprise Server prior to versions 22.2.10, 23.0.10, and 24.0.6 are vulnerable to a logged-in attacker slowing down the system by generating a lot of database/cpu load. Nextcloud Server versions 23.0.10 and 24.0.6 and Nextcloud Enterprise Server versions 22.2.10, 23.0.10, and 24.0.6 contain patches for this issue. As a workaround, disable the Circles app.

Profile of disabled user stays accessible

Nextcloud Server is the file server software for Nextcloud, a self-hosted productivity platform. Nextcloud Server and Nextcloud Enterprise Server prior to versions 23.0.9 and 24.0.5 are vulnerable to exposure of information that cannot be controlled by administrators without direct database access. Versions 23.0.9 and 24.0.5 contains patches for this issue. No known workarounds are available.

SMTP Command Injection in iCalendar Attachments to emails via newlines in Nextcloud Server

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: Propfind requests for file comments allowed to load comments for other files

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 31.0.0 to before 31.0.12, and 32.0.0 to before 32.0.3, a missing check of a relation allowed authenticated users with access to any file comment, to read the content of all comments. It is recommended that the Nextcloud Server is upgraded to 31.0.12 or 32.0.3. It is recommended that the Nextcloud Enterprise Server is upgraded to 21.0.9.20, 22.2.10.35, 23.0.12.31, 24.0.12.30, 25.0.13.25, 26.0.13.22, 27.1.11.22, 28.0.14.13, 29.0.16.10, 30.0.17.5, 31.0.12 or 32.0.3

Nextcloud: Bypass of second factor authentication on DAV endpoints

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, a pre-2FA session cookie (created after successful password authentication but before TOTP completion) could be reused as a Bearer token to authenticate against DAV endpoints, granting read/write access and bypassing mandatory two-factor authentication. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9 or 29.0.16.16

Nextcloud: Two-Factor Authentication Bypass via Pending Session Token Replay

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, an authentication bypass vulnerability allowed attackers with knowledge of a user's password to circumvent two-factor authentication (2FA) protections. When a user initiated login with valid credentials on a 2FA-enabled account, the system created a temporary session token before enforcing the second factor challenge. This token could be extracted and replayed via HTTP Basic Authentication to gain unauthorized access to authenticated endpoints. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9 or 29.0.16.16

Nextcloud: Hidden Public Link creation when sharing to a Team External Member

Nextcloud is an open source content collaboration platform. From versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, when a user shares a folder or file with a Nextcloud Team that includes an external member (a person added via email address who does not have a Nextcloud account), the system automatically creates a public link for that external member. This public link is not displayed in the share section of the folder, so the folder owner has no knowledge of its existence. It is sent via email to the external member. It grants the same permissions (read, write, delete, reshare, download) as the Team’s access. An attacker who receives or intercepts this link can access, modify, delete, reshare, and download all data in the shared folder without any further authentication. The folder owner cannot see or revoke the link through the normal sharing interface. This issue has been patched in versions 32.0.9 and 33.0.3.

Nextcloud: Limited path traversal via template API if using `{lang}` in config

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 31.0.0 to before 31.0.14, and 32.0.0 to before 32.0.4, if {lang} is used in the template directory config value, non-admin users can in some cases copy arbitrary files (depending on unix permissions) into their own Nextcloud directory via a path traversal. It is recommended that the Nextcloud Server is upgraded to 32.0.4, 31.0.14. It is recommended that the Nextcloud Enterprise Server is upgraded to 32.0.4, 31.0.14, 30.0.17.7, 29.0.17.12, 28.0.14.15

Nextcloud: Cross-Account Calendar Takeover via Unauthorized Group-Member-Set Update

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the attacker must be an authenticated user. This is because of improper authorization controls in the backend of the calendar. If the attacker had access to the calendar, they would be able to view and modify it. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17, 27.1.11.26, 26.0.13.26, 25.0.13.29, 24.0.12.34, 23.0.12.35, 22.2.10.39, or 21.0.9.23

Nextcloud: Logged-in user bypasses share password and download restrictions on Text attachments via documentId leads to unauthorized file access

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, an authenticated attacker can access attachments of link shares when knowing the share token, circumventing password protection or download restrictions. It is applicable to any file that is shared directly, as the attacker only needs to know a documentId they own, apart of the mentioned share token. For shared folders the attacker has to know or guess a documentId of a file that is included inside the folder, making it much harder to exploit. The attacker can only extract an attachments, but not the file shared file or folder itself. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17 or 27.1.11.5

Nextcloud: Files Lock app allows users to lock and unlock files of other users

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.2, and 33.0.0 to before 33.0.1, the files_lock app did not properly validate the ownership of files when processing DAV lock and unlock requests. An authenticated user could lock or unlock files belonging to other users by targeting their absolute WebDAV paths. Additionally, lock tokens were disclosed to unauthorized callers in error responses, allowing attackers to remove token-based locks placed by other users' client applications. It is recommended that the Nextcloud Server is upgraded to 32.0.2 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.14.4 or 32.0.2 or 33.0.1

Nextcloud: Valid share tokens allow to access tempory upload files of share owner

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, when a malicious user has access to a file share of a user, they could use this share token to also access the chunking upload directly and see temporary part files during on going uploads. It is recommended that the Nextcloud Server is upgraded to 32.0.9 or 33.0.3. It is recommended that the Nextcloud Enterprise Server is upgraded to 26.0.13.26, 27.1.11.25, 28.0.14.17, 29.0.16.16, 30.0.17.9, 31.0.14.5, 32.0.9 or 33.0.3

Cross-site scripting (XSS) vulnerability in a reachable files_pdfviewer example directory in Nextcloud with versions before 22.2.10.33, 23.0.12.29, 24.0.12.28, 25.0.13.23, 26.0.13.20, 27.1.11.20, 28.0.14.11, 29.0.16.8, 30.0.17, 31.0.10, and 32.0.1 allows attackers to execute arbitrary JavaScript in the context of a user's browser via a crafted PDF file to viewer.html. This issue is related to CVE-2024-4367, but the root cause of this Nextcloud issue is that the product exposes executable example code on a same-origin basis.