{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.2.2"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@clerk/backend"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.0.6"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@clerk/express"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.1.4"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@clerk/hono"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.1.0"
            },
            {
              "fixed": "0.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.4"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@clerk/fastify"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.1.0"
            },
            {
              "fixed": "3.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34076"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T19:58:19Z",
    "nvd_published_at": "2026-04-01T18:16:29Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe `clerkFrontendApiProxy` function in `@clerk/backend` is vulnerable to Server-Side Request Forgery (SSRF). An unauthenticated attacker can craft a request path that causes the proxy to send the application\u0027s `Clerk-Secret-Key` to an attacker-controlled server.\n\n## Affected packages\n\nOnly applications that have opted into the `frontendApiProxy` feature are affected. This feature is not enabled by default. **Users of `@clerk/nextjs` are not affected** due to how the framework handles repeated `/` in request paths.\n\n| Package | Affected versions | Fixed version |\n|---|---|---|\n| `@clerk/backend` | `\u003e= 3.0.0, \u003c= 3.2.2` | `3.2.3` |\n| `@clerk/express` | `\u003e= 2.0.0, \u003c= 2.0.6` | `2.0.7` |\n| `@clerk/hono` | `\u003e= 0.1.0, \u003c= 0.1.4` | `0.1.5` |\n| `@clerk/fastify` | `\u003e= 3.1.0, \u003c= 3.1.4` | `3.1.5` |\n\nSearch your codebase for the `frontendApiProxy` option. If none of the patterns below appear in your code, you are not affected.\n\n**@clerk/express**\n```ts\napp.use(clerkMiddleware({ frontendApiProxy: { enabled: true } }));\n```\n\n**@clerk/hono**\n```ts\napp.use(\u0027*\u0027, clerkMiddleware({ frontendApiProxy: { enabled: true } }));\n```\n\n**@clerk/fastify**\n```ts\nfastify.register(clerkPlugin, { frontendApiProxy: { enabled: true } });\n```\n\n**@clerk/backend**\n```ts\nimport { clerkFrontendApiProxy } from \u0027@clerk/backend/proxy\u0027;\n```\n\nA quick way to check across your entire project:\n\n```sh\ngrep -r \"frontendApiProxy\\|clerkFrontendApiProxy\" .\n```\n\nIf there are no matches, you are not using this feature.\n\n\n## Recommended actions\n\nClerk\u0027s internal logs show no evidence of users utilizing the built-in proxy with the impacted versions. Despite that, if you are on an impacted version and use the built-in proxy we recommend upgrading and rotating your Clerk Secret Key immediately.\n\n1. **Upgrade** to the patched version of `@clerk/backend` (and `@clerk/express`, `@clerk/hono`, etc.)\n2. **Rotate your Clerk Secret Key** after upgrading - if an attacker exploited this vulnerability, they may have captured your key. Rotate it in the [Clerk Dashboard](https://dashboard.clerk.com) under **API Keys**.  You should deploy your application with the updated key before revoking the existing key.\n3. **Audit access logs** for requests to your proxy endpoint (`/__clerk/` by default) containing double slashes in the path.\n\n\n\n## Credit\n\nDiscovered during an internal code audit.",
  "id": "GHSA-gjxx-92w9-8v8f",
  "modified": "2026-04-06T16:44:03Z",
  "published": "2026-03-27T19:58:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/clerk/javascript/security/advisories/GHSA-gjxx-92w9-8v8f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34076"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/clerk/javascript"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Clerk: SSRF in the opt-in clerkFrontendApiProxy feature may leak secret keys to unintended host"
}