CVE-2026-42861
FlowiseAI has Mass Assignment in Variable Update Endpoint that Allows Cross-Workspace Resource Reassignment
Description
### Summary A Mass Assignment vulnerability exists in the variable update endpoint of FlowiseAI. The endpoint allows authenticated users to modify server-controlled properties such as workspaceId, createdDate, and updatedDate when updating a variable resource. Due to missing server-side validation and authorization checks, an attacker can manipulate the workspaceId field and reassign variables to arbitrary workspaces. This behavior may break tenant isolation in multi-workspace environments. ### Details The endpoint responsible for updating variables: **PUT /api/v1/variables/{variableId}** accepts a JSON request body containing the variable definition. However, the backend does not restrict which attributes can be modified by the client. As a result, user-controlled request bodies can include internal properties that should normally be controlled exclusively by the server. Server-controlled fields that can be manipulated include: - workspaceId - createdDate - updatedDate These fields appear to be directly mapped to the database entity without strict input validation or authorization checks. For example, the following request body was accepted by the server: ```json { "name": "aaa", "value": "bbbe", "type": "static", "createdDate": "2016-03-06T17:59:30.000Z", "updatedDate": "2016-03-06T18:00:17.000Z", "workspaceId": "11111111-2222-3333-4444-555555555555" } ``` The server accepted the attacker-controlled workspaceId and metadata fields and persisted them. ### PoC **Request** ```http PUT /api/v1/variables/<VARIABLE_ID> Content-Type: application/json { "name": "aaa", "value": "bbbe", "type": "static", "createdDate": "2016-03-06T17:59:30.000Z", "updatedDate": "2016-03-06T18:00:17.000Z", "workspaceId": "11111111-2222-3333-4444-555555555555" } ``` **Response** ```json { "id": "0a2b9f61-4a97-4ff8-b80d-00275ed18674", "name": "aaa", "value": "bbbe", "type": "static", "createdDate": "2016-03-06T17:59:30.000Z", "updatedDate": "2026-03-06T18:05:17.000Z", "workspaceId": "11111111-2222-3333-4444-555555555555" } ``` This confirms that the backend accepts and persists attacker-controlled internal properties. ### Impact This vulnerability allows authenticated users to manipulate internal attributes of variable resources. Possible impacts include: 1. Cross-workspace reassignment of variables (workspaceId) 2. Unauthorized modification of metadata (createdDate, updatedDate) 3. Potential tenant isolation bypass in multi-workspace deployments In multi-tenant environments, this may allow an attacker to move variables between workspaces without authorization.
How to fix CVE-2026-42861
To remediate CVE-2026-42861, upgrade the affected package to a fixed version below.