File owners were unable to unlock TYPE_TOKEN locks placed by other users, leaving files permanently locked with no recovery path outside of the database.
The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items.
After guessing a 62^15 complex unique identifier, a malicious logged in user was able to retrieve a list of memberships for a circle they are not a member of.
The Photos app's filter-based "smart albums" build their file listing using the search configuration (photosSourceFolders) of the user viewing the album, rather than the album owner's configuration. When an album owner shares a smart album with another user, that user's own folder configuration is used to determine which of the owner's files are searched — allowing them to discover files (name, file ID, and other metadata) in folders the album owner never intended to include in the shared album.
This requires the album owner to have shared a filter-based smart album with the attacker; it does not allow access to arbitrary users' files without such a share.
Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before trust in the remote instance is established, and explicitly allows local/private addresses for this request, bypassing Nextcloud's core SSRF protections. The public, unauthenticated endpoints POST /apps/circles/event/ and POST /apps/circles/incoming/ reach this code path, allowing any unauthenticated user to force the server to issue a GET request to an internal address.
The response body of the internal request is never returned to the requester, so this is blind SSRF: an attacker can determine whether an internal service is reachable, but cannot read its response contents through this endpoint alone.
The Deck config API allows authenticated users to set board-scoped configuration keys for arbitrary board IDs without validating whether the user owns or has permission to manage the referenced board.
The Approval app's approve/reject endpoint is meant to require the file's current etag as a freshness check, preventing an approver from approving or rejecting a file whose contents changed after they reviewed it. The backend only enforced this check when the etag parameter was present and non-empty in the request. An attacker able to intercept and modify the approval request could omit the etag field entirely, bypassing the freshness check and approving or rejecting a file version they never reviewed.
A vulnerability in the team folders (formerly group folders) app when used in combination with the workspace app allowed API/REST-only delegated administrators to bypass folder-level authorization controls. The workspace app enables organizations to delegate limited administrative privileges for team folder management via API/REST only, restricting access to folders for which the admin has advanced permissions.
Any authenticated user can lock or unlock files they do not own by targeting absolute WebDAV paths of other users. The DAV plugin resolves files from the absolute request URI without verifying that the path segment matches the authenticated session user. This enables:
Cross-user manual locks : attacker locks a victim's files, blocking writes (PUT/MOVE/DELETE, editor saves).
Lock-token disclosure: the app returns the lock token to unauthorized callers, enabling them to remove token-based locks (client locks) of other users.
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 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 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 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 versions 0.9.0 to before 0.9.7 and 1.0.0 to before 1.0.2 contain a SQL injection vulnerability in the Tables app due to missing sanitization in the ORDER BY clause of a query. This flaw allows a user with access to the Tables app to perform limited SQL injection attacks that can extract a single bit of information per request or cause the database to delay responses.
Nextcloud is an open source content collaboration platform. From versions 0.7.0 to before 0.7.7, 0.8.0 to before 0.8.10, 0.9.0 to before 0.9.8, and 1.0.0 to before 1.0.4, an authenticated attacker with access to the Tables app may be able to execute arbitrary up to 20 bytes long SQL queries, through a stored injection. With carefully crafted input it is possible to break out of the length limitation. The attacker could use this to extract information from the database, or modify data. This issue has been patched in versions 0.7.7, 0.8.10, 0.9.8, 1.0.4, and 2.0.0.
Nextcloud versions from 0.8.0 up to but not including 1.0.4 have a vulnerability where view filter criteria in Nextcloud Tables are exposed to users with read-only permissions. This exposure of metadata could reveal sensitive information unintentionally. The issue has been addressed and patched in versions 1.0.4 and later.
Nextcloud versions from 4.3.0 up to but not including 5.2.7 contain a vulnerability where a removed collaborator retains unauthorized read access to uploaded respondent files for forms they previously had access to. This issue is limited to files associated with those specific forms. The vulnerability has been addressed and patched in version 5.2.7.
Nextcloud versions 5.5.13 to before 5.5.17 and 6.2.0 to before 6.2.3 contain a vulnerability where an authenticated user can enumerate other users on the same instance via the Calendar app's attendee suggestion endpoint. This endpoint did not enforce sharing restrictions that were applied elsewhere, leading to exposure of user information.
Nextcloud is an open source content collaboration platform. From version 1.3.6 to before version 8.4.0, an improper check allowed users that where provided by LDAP to still authenticate towards user OIDC after they where deleted. This issue has been patched in version 8.4.0.
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.