Hono: `serveStatic` decodes the request path a second time, leading to bypass of middleware on static paths

{
  "id": "84ac8f10b051e85cc6665bb84dbf5af8fef2bb0a55bc81c38ae1b0b079bffdd1",
  "url": "https://osv.dev/vulnerability/CVE-2026-111757",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Hono: `serveStatic` decodes the request path a second time, leading to bypass of middleware on static paths",
    "summary": "Hono is a Web application framework that provides support for any JavaScript runtime. From 4.12.4 until 4.13.11, serveStatic can interpret a malformed percent-encoded path differently from upstream routing middleware and bypass protection for a static prefix. The root cause is serveStatic decodes a routed request path a second time before filesystem lookup. The attack mechanism is malformed percent encoding survives the first routing interpretation and becomes a protected path only during the later static-file decode. The affected component is serveStatic. The trigger conditions are an application protects a static prefix with upstream middleware and serveStatic receives an attacker-controlled malformed percent-encoded path. The impact is unauthorized disclosure of a static file that upstream middleware was intended to protect. The issue does not permit traversal outside the configured static root. This issue is fixed in version 4.13.11.",
    "evidence": "osv:CVE-2026-111757",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-111757",
      "aliases": [
        "CVE-2026-109955",
        "CVE-2026-111757",
        "GHSA-5r4p-p66f-jhc7"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/honojs/hono",
              "type": "GIT",
              "events": [
                {
                  "introduced": "19d20d23a2921e26c3bbfdb5549fce98b4a39b28"
                },
                {
                  "fixed": "37ce06904e732d4bc11c9075adf362c76049a594"
                },
                {
                  "fixed": "8b05c774ef1555c70f5ba5e2991b7e77cc3635cc"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "4.12.4"
                      },
                      {
                        "fixed": "4.13.11"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8b05c774ef1555c70f5ba5e2991b7e77cc3635cc"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "@hono/netlify@1.0.1",
            "@hono/deno@1.0.2",
            "@hono/deno@1.0.1",
            "v4.13.10",
            "v4.13.9",
            "v4.13.8",
            "v4.13.7",
            "v4.13.6",
            "v4.13.5",
            "v4.13.4",
            "v4.13.1",
            "v4.13.3",
            "v4.13.2",
            "v4.13.0",
            "v4.12.34",
            "v4.12.33",
            "v4.12.32",
            "v4.12.31",
            "v4.12.30",
            "v4.12.29",
            "v4.12.28",
            "v4.12.27",
            "v4.12.26",
            "v4.12.25",
            "v4.12.24",
            "v4.12.23",
            "v4.12.22",
            "v4.12.21",
            "v4.12.20",
            "v4.12.19",
            "v4.12.18",
            "v4.12.17",
            "v4.12.16",
            "v4.12.15",
            "v4.12.14",
            "v4.12.13",
            "v4.12.12",
            "v4.12.11",
            "v4.12.10",
            "v4.12.9",
            "v4.12.8",
            "v4.12.7",
            "v4.12.6",
            "v4.12.5",
            "v4.12.4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-111757.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.902456003Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111757.json",
        "https://github.com/honojs/hono/security/advisories/GHSA-5r4p-p66f-jhc7",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-111757",
        "https://github.com/honojs/hono/commit/8b05c774ef1555c70f5ba5e2991b7e77cc3635cc"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-174"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111757.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-109955",
        "evidence": "/aliases"
      },
      {
        "value": "CVE-2026-111757",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492602,
  "published_at": "2026-10-19T17:31:20.341+00:00"
}