{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-beta.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "waku"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.0-beta.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49456"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-08T20:30:21Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "## Summary\n\nThe `unstable_redirect()` helper exported from `waku/router/server` (`packages/waku/src/router/define-router.tsx:156\u2013161`) accepts an arbitrary string and reflects it unchanged into the HTTP `Location` response header with no URL validation, scheme restriction, or path-only enforcement. Any application that passes user-controlled input to this helper \u2014 the natural pattern documented in the JSDoc and official fixtures \u2014 is vulnerable to open redirect attacks. An attacker who convinces a victim to click a crafted link can silently redirect the browser to an arbitrary external domain, enabling phishing, credential harvesting, and OAuth token theft. Additionally, scheme-relative URLs (`//evil.example/`) bypass naive `https?://`-only allow-list filters that developers might add as ad-hoc mitigations.\n\nDynamic PoC confirmed against **waku 1.0.0-beta.0** (commit `8e9f542`) in an isolated Docker environment. Two independent dynamic runs produced identical results.\n\n---\n\n## Root Cause\n\n`packages/waku/src/router/define-router.tsx:156\u2013161`:\n\n```ts\nexport function unstable_redirect(\n  location: string, // only URL `pathname` is supported.\n  status: 303 | 307 | 308 = 307,\n): never {\n  throw createCustomError(\u0027Redirect\u0027, { status, location });\n}\n```\n\nThe JSDoc comment states \"only URL `pathname` is supported\", but this constraint is expressed as documentation only \u2014 the function performs **no validation**. The `location` value propagates via `createCustomError` (`custom-errors.ts:22\u201326`) into an error digest, is recovered by `getErrorInfo` in the request handler (`handler.ts:79\u201389`), and reflected directly into `headers.location` of the outgoing `Response` with no sanitization:\n\n```ts\nif (info?.location) {\n  headers.location = info.location;   // handler.ts:87 \u2014 unvalidated reflection\n}\nreturn new Response(body, { status, headers });\n```\n\n---\n\n## Trigger (one-line summary)\n\nAny developer-supplied user input passed to `unstable_redirect()` is reflected unchanged into the HTTP `Location` header, enabling navigation to an attacker-controlled domain.\n\n---\n\n## Affected Entry Surfaces\n\n- `unstable_redirect(location, status?)` \u2014 `waku/router/server` public export\n- Any page/route component that passes `searchParams`, `query`, or other user-\n  controlled strings to `unstable_redirect` (the standard post-login or callback\n  redirect pattern)\n- All waku adapters (Node.js, Cloudflare Workers, Vercel Edge, Deno) share the same\n  `handler.ts` reflection path; cross-runtime CRLF parity is unaudited (see note\n  below)\n\n---\n\n## Additional Defense-in-Depth Concern\n\nOn Node.js, CRLF injection via the `Location` header is rejected by `node:_http_outgoing.setHeader` (`ERR_INVALID_CHAR`). This defense is **platform-specific** and not present in the waku source. Cloudflare Workers, Deno Deploy, and other edge runtimes have not been verified to offer equivalent protection. A cross-runtime audit is recommended.\n\n---\n\n## Suggested Fix Outline\n\nValidate the `location` argument inside `unstable_redirect` before the error is thrown: reject any value that does not begin with a single `/` (no `//`), and reject any value containing control characters (`\\x00`\u2013`\\x1f`). An opt-in allow-list for intentional cross-origin redirects can be provided via a framework configuration option.\n\n---\n\n## Disclosure\n\n| Field            | Value                              |\n|------------------|------------------------------------|\n| Reporter         | j0hndo (`dohyun4466@gmail.com`)    |\n| Discovery date   | 2026-05-17                         |\n| Embargo          | 90 days from acknowledgment        |\n| Patched version  | Not yet available                  |\n| Public references| CWE-601; OWASP A01:2021            |",
  "id": "GHSA-43fc-v873-qw85",
  "modified": "2026-07-08T20:30:21Z",
  "published": "2026-07-08T20:30:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wakujs/waku/security/advisories/GHSA-43fc-v873-qw85"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wakujs/waku"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wakujs/waku/releases/tag/v1.0.0-beta.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Waku has an Open Redirect via `unstable_redirect` Helper"
}