Hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`)_CVE-2026-54286

{
    "lastseen": "",
    "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.",
    "published": "2026-06-22T17:14:40.133Z",
    "modified": "2026-06-22T17:14:40.133Z",
    "type": "cve",
    "title": "Hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`)",
    "source": "GitHub_M",
    "references": "https://github.com/honojs/hono/security/advisories/GHSA-wwfh-h76j-fc44",
    "id": "CVE-2026-54286",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22"
    ],
    "cvelist": null,
    "sourceData": "honojs hono < 4.12.25",
    "sourceHref": "",
    "cvss": {
        "score": 5.9,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "hono",
    "version": "< 4.12.25",
    "vendor": "honojs",
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    "ai_score": 0
}