CVE-2026-33490
H3 is a minimal H(TTP) framework. In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Puntuación base: 5.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.28%
- Percentil entre todas las CVEs puntuadas: 19
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-706
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-33490",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-33490",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-03-26T17:46:14.997707Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 3.7,
"attackVector": "NETWORK",
"baseSeverity": "LOW",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
"integrityImpact": "LOW",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 1.4,
"exploitabilityScore": 2.2
},
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 5.3,
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"integrityImpact": "LOW",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 1.4,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "h3js",
"product": "h3",
"versions": [
{
"status": "affected",
"version": ">= 2.0.1-alpha.0, < 2.0.1-rc.17"
}
]
}
]
}
],
"published": "2026-03-26T18:16:30.237",
"references": [
{
"url": "https://github.com/h3js/h3/security/advisories/GHSA-2j6q-whv2-gh6w",
"tags": [
"Exploit",
"Mitigation",
"Vendor Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/h3js/h3/security/advisories/GHSA-2j6q-whv2-gh6w",
"tags": [
"Exploit",
"Mitigation",
"Vendor Advisory"
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Analyzed",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-706"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "H3 is a minimal H(TTP) framework. In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch."
},
{
"lang": "es",
"value": "H3 es un framework H(TTP) mínimo. En las versiones 2.0.0-0 hasta la 2.0.1-rc.16, el método 'mount()' en h3 usa una simple verificación 'startsWith()' para determinar si las solicitudes entrantes caen bajo el prefijo de ruta de una subaplicación montada. Debido a que esta verificación no verifica un límite de segmento de ruta (es decir, que el siguiente carácter después de la base es '/' o el final de la cadena), el middleware registrado en un montaje como '/admin' también se ejecutará para rutas no relacionadas como '/admin-public', '/administrator' o '/adminstuff'. Esto permite a un atacante activar middleware de configuración de contexto en rutas que nunca se pretendió cubrir, potencialmente contaminando el contexto de la solicitud con indicadores de privilegio no deseados. La versión 2.0.2-rc.17 contiene un parche."
}
],
"lastModified": "2026-06-17T10:37:35.357",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc1:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "910077BC-C84C-4CAB-A0A5-761047F6F43C"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc10:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "603A08FC-B20B-4693-90A1-0BF5F08B43AC"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc11:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "BCC5ECF0-0EED-48BC-95FA-1D2671A971A9"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc12:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "BCCBE75E-DCF6-45FD-B57E-F8E2ADE3129F"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc13:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "3B66082C-3F3E-4BC6-9543-A2F9CFE3AAC6"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc14:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "3D1C9D7B-3CE4-427B-93B4-EAF867159AFB"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc15:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "5AE7D8A6-4506-418A-ABA4-C820A1DA7E7F"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc16:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "281715D9-6C86-4D4E-9833-C18A8CABD05A"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc2:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "C5E7779A-00CA-45E7-8F68-1DAB5388ED4A"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc3:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "064C21F5-8633-45F3-9A3D-3FB029A867B9"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc4:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "DDBC1DFD-8063-4AE1-92D8-B3B33735FEF0"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc5:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "496314A3-8F2B-4274-9D0D-7F11E896FEA5"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc6:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "35F49342-D52C-4762-9369-F380C5E7E0B5"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc7:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "D11CA1A7-3141-46EA-9687-32C333FC7B0C"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc8:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "A4A6FD03-5DE5-4D73-9FF3-BB653302C60B"
},
{
"criteria": "cpe:2.3:a:h3:h3:2.0.1:rc9:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "5E404148-6862-44F5-961D-10E8A742A4B6"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security-advisories@github.com"
}