CVE-2023-43622
Estado: ModificadaAlta (7.5)—
An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout.
This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57.
Users are recommended to upgrade to version 2.4.58, which fixes the issue.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 7.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 71%
- Percentil entre todas las CVEs puntuadas: 99
- Fecha de la puntuación: 6/10/2026
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-400
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2023-43622",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2023-43622",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2024-09-11T16:02:28.689513Z"
}
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.5,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "security@apache.org",
"affectedData": [
{
"vendor": "Apache Software Foundation",
"product": "Apache HTTP Server",
"versions": [
{
"status": "affected",
"version": "2.4.55",
"versionType": "semver",
"lessThanOrEqual": "2.4.57"
}
],
"defaultStatus": "unaffected"
}
]
}
],
"published": "2023-10-23T07:15:11.243",
"references": [
{
"url": "https://httpd.apache.org/security/vulnerabilities_24.html",
"tags": [
"Vendor Advisory"
],
"source": "security@apache.org"
},
{
"url": "https://security.netapp.com/advisory/ntap-20231027-0011/",
"tags": [
"Third Party Advisory"
],
"source": "security@apache.org"
},
{
"url": "https://httpd.apache.org/security/vulnerabilities_24.html",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://security.netapp.com/advisory/ntap-20231027-0011/",
"tags": [
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Secondary",
"source": "security@apache.org",
"description": [
{
"lang": "en",
"value": "CWE-400"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known \"slow loris\" attack pattern.\nThis has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout.\n\nThis issue affects Apache HTTP Server: from 2.4.55 through 2.4.57.\n\nUsers are recommended to upgrade to version 2.4.58, which fixes the issue."
},
{
"lang": "es",
"value": "Un atacante, al abrir una conexión HTTP/2 con un tamaño de ventana inicial de 0, pudo bloquear el manejo de esa conexión indefinidamente en el servidor HTTP Apache. Esto podría usarse para agotar los recursos de los trabajadores en el servidor, similar al conocido patrón de ataque \"slow loris\". Esto se solucionó en la versión 2.4.58, de modo que dicha conexión finalice correctamente después del tiempo de espera de conexión configurado. Este problema afecta al servidor HTTP Apache: desde 2.4.55 hasta 2.4.57. Se recomienda a los usuarios actualizar a la versión 2.4.58, que soluciona el problema."
}
],
"lastModified": "2026-06-17T06:26:05.477",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "F9F28355-B47B-463B-862A-E493D0743CC9",
"versionEndExcluding": "2.4.58",
"versionStartIncluding": "2.4.55"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security@apache.org"
}