{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-126357",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-11-10T21:12:01.227Z",
        "datePublished": "2026-11-12T22:18:46.437Z",
        "dateUpdated": "2026-11-12T22:18:46.437Z"
    },
    "containers": {
        "cna": {
            "title": "Hono: `mount()` and `app.mount()` can forward a path that bypasses middleware scoped inside the mount prefix",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-288",
                            "lang": "en",
                            "description": "CWE-288: Authentication Bypass Using an Alternate Path or Channel",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/honojs/hono/security/advisories/GHSA-4m76-xfj5-7975",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/honojs/hono/security/advisories/GHSA-4m76-xfj5-7975"
                },
                {
                    "name": "https://github.com/honojs/hono/commit/34f90432a1794b28e52802670efcd01963f716d6",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/honojs/hono/commit/34f90432a1794b28e52802670efcd01963f716d6"
                },
                {
                    "name": "https://github.com/honojs/hono/releases/tag/v4.13.16",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/honojs/hono/releases/tag/v4.13.16"
                }
            ],
            "affected": [
                {
                    "vendor": "honojs",
                    "product": "hono",
                    "versions": [
                        {
                            "version": "< 4.13.16",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-11-12T22:18:46.437Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.16, mount() and app.mount() can remove a dynamic mount prefix using the route-pattern length rather than the matched-prefix length, allowing a crafted path to be forwarded as a protected inner route while the outer application routes the original path. Since 4.12.21, rebuilding the forwarded URL from the decoded pathname can also convert a decoded backslash to a slash and collapse parent-directory segments, again causing the mounted application to receive a protected path. An unauthenticated client can use either applicable path transformation to reach a mounted route without authentication or authorization middleware scoped to a subpath inside the mount prefix. This issue is fixed in version 4.13.16."
                }
            ],
            "source": {
                "advisory": "GHSA-4m76-xfj5-7975",
                "discovery": "UNKNOWN"
            }
        }
    }
}