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CVE-2026-54286

Full vulnerability record from the local CVENow database.

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on Windows hosts, an encoded backslash (%5C) in the request path decodes to \, which the Windows path resolver treats as a separator. serve-static then resolves a single URL segment such as admin\secret.txt into a nested file under the root and serves it, letting an attacker read static files meant to be protected behind prefix-mounted middleware. This vulnerability is fixed in 4.12.25.

Severity
MEDIUM
CVSS score
5.9 (v3.1)
Vulnerability status
Deferred
Source identifier
Published
2026-06-22 18:16:47.213000
Last modified
2026-10-25 23:10:00.167000
View original CVE JSON
{
  "id": "CVE-2026-54286",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-22T18:16:47.213",
  "lastModified": "2026-10-25T23:10:00.167",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on Windows hosts, an encoded backslash (%5C) in the request path decodes to \\, which the Windows path resolver treats as a separator. serve-static then resolves a single URL segment such as admin\\secret.txt into a nested file under the root and serves it, letting an attacker read static files meant to be protected behind prefix-mounted middleware. This vulnerability is fixed in 4.12.25."
    },
    {
      "lang": "es",
      "value": "Hono es un framework de aplicación web que proporciona soporte para cualquier entorno de ejecución de JavaScript. Antes de la versión 4.12.25, en hosts de Windows, una barra invertida codificada (%5C) en la ruta de la solicitud se decodifica a \\, que el resolvedor de rutas de Windows trata como un separador. serve-static entonces resuelve un único segmento de URL como admin\\secret.txt en un archivo anidado bajo la raíz y lo sirve, permitiendo a un atacante leer archivos estáticos destinados a ser protegidos detrás de un middleware montado con prefijo. Esta vulnerabilidad está corregida en la versión 4.12.25."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "honojs",
          "product": "hono",
          "versions": [
            {
              "version": "< 4.12.25",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-06-23T14:07:25.570505Z",
          "id": "CVE-2026-54286",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-wwfh-h76j-fc44",
      "source": "[email protected]"
    }
  ]
}