CVE-2026-25651: Client certificate auth Client-certificate-auth Vulnerable To Open Redirect Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-m4w9-gch5-c2g4",
  "modified" : "2026-02-06T21:43:18Z",
  "published" : "2026-02-06T18:54:33Z",
  "aliases" : [ "CVE-2026-25651" ],
  "summary" : "client-certificate-auth Vulnerable to Open Redirect via Host Header Injection in HTTP-to-HTTPS redirect",
  "details" : "### Summary\n\nVersions 0.2.1 and 0.3.0 of `client-certificate-auth` contain an open redirect vulnerability. The middleware unconditionally redirects HTTP requests to HTTPS using the unvalidated `Host` header, allowing an attacker to redirect users to arbitrary domains.\n\n### Vulnerable Code\n\n```javascript\n// lib/clientCertificateAuth.js (versions 0.2.1, 0.3.0)\nif (!req.secure && req.header('x-forwarded-proto') != 'https') {\n  return res.redirect('https://' + req.header('host') + req.url);\n}\n```\n\n### Attack Scenario\n\n1. Attacker crafts a link: `http://vulnerable-app.example.com/login`\n2. When victim clicks, attacker intercepts and injects header: `Host: attacker.com`\n3. Server responds: `302 Found → https://attacker.com/login`\n4. Victim is redirected to attacker-controlled site\n\n### Impact\n\n- **Phishing**: Attackers can use trusted domain links to redirect victims to credential-harvesting pages\n- **OAuth/SSO Token Theft**: In authentication flows, authorization codes or tokens may leak via redirect\n- **Referer Leakage**: Sensitive URL parameters may be exposed to attacker domains via the Referer header\n- **Cache Poisoning**: In deployments with shared caches, malicious redirects may be cached and served to other users\n\n### Exploitability\n\nExploitation requires that HTTP traffic reaches the Node.js application without TLS termination setting `x-forwarded-proto: https`. This condition is uncommon in production deployments behind modern reverse proxies or load balancers, which limits real-world exploitability.\n\n### Fix\n\nThe vulnerable redirect behavior has been completely removed in version 1.0.0.\n\n```bash\nnpm install client-certificate-auth@^1.0.0\n```\n\n### Workarounds\n\nIf upgrading is not immediately possible:\n\n1. Block HTTP traffic at the network/load balancer level\n2. Ensure your reverse proxy always sets `x-forwarded-proto: https`\n3. Add middleware before `clientCertificateAuth` to validate the `Host` header against an allowlist\n\n### References\n\n- [CWE-601: URL Redirection to Untrusted Site](https://cwe.mitre.org/data/definitions/601.html)\n- [OWASP: Unvalidated Redirects and Forwards](https://cheatsheetseries.owasp.org/cheatsheets/Unvalidated_Redirects_and_Forwards_Cheat_Sheet.html)\n- [Fix Commit](https://github.com/tgies/client-certificate-auth/commit/8fc995e953db483495be46862965e50fe9e1cc52)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "client-certificate-auth"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.2.1"
      }, {
        "fixed" : "1.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/tgies/client-certificate-auth/security/advisories/GHSA-m4w9-gch5-c2g4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-25651"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tgies/client-certificate-auth/commit/8fc995e953db483495be46862965e50fe9e1cc52"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/tgies/client-certificate-auth"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tgies/client-certificate-auth/releases/tag/v1.0.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-06T18:54:33Z",
    "nvd_published_at" : "2026-02-06T19:16:09Z"
  }
}