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GHSA-Q5QW-H33P-QVWR

Vulnerability from github – Published: 2026-03-04 19:48 – Updated: 2026-03-05 15:26
VLAI
Summary
Hono vulnerable to arbitrary file access via serveStatic vulnerability
Details

Summary

When using serveStatic together with route-based middleware protections (e.g. app.use('/admin/*', ...)), inconsistent URL decoding allowed protected static resources to be accessed without authorization.

The router used decodeURI, while serveStatic used decodeURIComponent. This mismatch allowed paths containing encoded slashes (%2F) to bypass middleware protections while still resolving to the intended filesystem path.

Details

The routing layer preserved %2F as a literal string, while serveStatic decoded it into / before resolving the file path.

Example:

Request: /admin%2Fsecret.html

  • Router sees: /admin%2Fsecret.html → does not match /admin/*
  • Static handler resolves: /admin/secret.html

As a result, static files under the configured static root could be served without triggering route-based protections.

This only affects applications that both:

  • Protect subpaths using route-based middleware, and
  • Serve files from the same static root using serveStatic.

This does not allow access outside the static root and is not a path traversal vulnerability.

Impact

An unauthenticated attacker could bypass route-based authorization for protected static resources by supplying paths containing encoded slashes.

Applications relying solely on route-based middleware to protect static subpaths may have exposed those resources.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hono"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.12.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-29045"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-177"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-04T19:48:00Z",
    "nvd_published_at": "2026-03-04T23:16:10Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nWhen using `serveStatic` together with route-based middleware protections (e.g. `app.use(\u0027/admin/*\u0027, ...)`), inconsistent URL decoding allowed protected static resources to be accessed without authorization.\n\nThe router used `decodeURI`, while `serveStatic` used `decodeURIComponent`. This mismatch allowed paths containing encoded slashes (`%2F`) to bypass middleware protections while still resolving to the intended filesystem path.\n\n\n## Details\n\nThe routing layer preserved `%2F` as a literal string, while `serveStatic` decoded it into `/` before resolving the file path.\n\nExample:\n\nRequest: `/admin%2Fsecret.html`\n\n- Router sees: `/admin%2Fsecret.html` \u2192 does not match `/admin/*`\n- Static handler resolves: `/admin/secret.html`\n\nAs a result, static files under the configured static root could be served without triggering route-based protections.\n\nThis only affects applications that both:\n\n- Protect subpaths using route-based middleware, and\n- Serve files from the same static root using `serveStatic`.\n\nThis does **not** allow access outside the static root and is **not** a path traversal vulnerability.\n\n\n## Impact\n\nAn unauthenticated attacker could bypass route-based authorization for protected static resources by supplying paths containing encoded slashes.\n\nApplications relying solely on route-based middleware to protect static subpaths may have exposed those resources.",
  "id": "GHSA-q5qw-h33p-qvwr",
  "modified": "2026-03-05T15:26:34Z",
  "published": "2026-03-04T19:48:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-29045"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/commit/6a0607a929d888893f0c91d92dce2fcfdb3662a3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/honojs/hono"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Hono vulnerable to arbitrary file access via serveStatic vulnerability "
}



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