CVE-2026-49456: Waku Waku Has An Open Redirect Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-43fc-v873-qw85",
  "modified" : "2026-07-08T20:30:21Z",
  "published" : "2026-07-08T20:30:21Z",
  "aliases" : [ "CVE-2026-49456" ],
  "summary" : "Waku has an Open Redirect via `unstable_redirect` Helper",
  "details" : "## Summary\n\nThe `unstable_redirect()` helper exported from `waku/router/server` (`packages/waku/src/router/define-router.tsx:156–161`) 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 — the natural pattern documented in the JSDoc and official fixtures — 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:156–161`:\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('Redirect', { status, location });\n}\n```\n\nThe JSDoc comment states \"only URL `pathname` is supported\", but this constraint is expressed as documentation only — the function performs **no validation**. The `location` value propagates via `createCustomError` (`custom-errors.ts:22–26`) into an error digest, is recovered by `getErrorInfo` in the request handler (`handler.ts:79–89`), 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 — 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?)` — `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`–`\\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            |",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "waku"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.0.0-beta.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.0.0-beta.0"
    }
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-08T20:30:21Z",
    "nvd_published_at" : null
  }
}