{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.0-beta.63"
      },
      "package": {
        "ecosystem": "npm",
        "name": "workflow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.2.0-beta.64"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.0-beta.63"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@workflow/core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.2.0-beta.64"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-06T18:45:02Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "`createWebhook()` in Vercel Workflow DevKit accepts a user-specified `token` parameter that serves as the credential for the public webhook endpoint `/.well-known/workflow/v1/webhook/{token}`. Official documentation recommended predictable token patterns, making it possible for an unauthenticated remote attacker to guess the token and inject arbitrary payloads into the workflow execution context.\n\n#### Impact\n\nAn attacker who guesses a webhook token can resume the associated workflow with an attacker-controlled HTTP request body, potentially triggering downstream side effects such as API calls, database writes, or deployments.\n\n#### Fix\n\n* Upgrade to version 4.2.0-beta.64. The fix removes the `token` option from `createWebhook()` so that webhook tokens are always randomly generated by the SDK.\n* Runs created with versions prior to 4.2.0-beta.64, that are 1) still active (i.e. running), and 2) have open hooks, are still susceptible to this vulnerability. If users suspect the hook tokens are predictable or leaked - consider cancelling those runs and restarting them on the latest patch.\n\n#### Workarounds\n\nIn case a version upgrade is not possible, avoid passing predictable or guessable values to the `token` parameter of `createWebhook()`. Instead, users can either\n\n* switch from `createWebhook()` to `createHook()` instead and programmatically resume hooks using `resumeHook()` instead of the public webhook endpoint, or\n* use `createWebhook()` without passing a user-provided `token`, which uses a non-guessable random `nanoid` by default.",
  "id": "GHSA-9r75-g2cr-3h76",
  "modified": "2026-03-06T18:45:02Z",
  "published": "2026-03-06T18:45:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vercel/workflow/security/advisories/GHSA-9r75-g2cr-3h76"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vercel/workflow/commit/30e24d441e735635ffa4522198e6905d0e51e175"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vercel/workflow"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vercel/workflow/releases/tag/workflow%404.2.0-beta.64"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Vercel Workflow Allows Webhook Creation with Predictable User-Specified Tokens"
}