CVE-2026-89092
Full vulnerability record from the local CVENow database.
Description
The nscd service in the GNU C Library 2.3.4 onwards may crash due to a stack overflow when a malicious DNS server returns too large a response for a DNS query, resulting in degraded DNS resolution for the system. Exploitation of this bug needs a system that has nscd enabled and using an untrusted DNS server for name resolution, with the compromised DNS server being capable of processing records large enough to result in a stack overflow in an nscd thread stack. During experimentation, bind 9 was unable to handle large records, but that could change in future or with a different name server. In typical installations, nscd is executed in an isolated context as its own user without a shell, due to which any compromise of that service is isolated. There is a remote possibility of nscd cache corruption if an attacker manages to get the stack pointer into a desired point in the heap, potentially resulting in other caches in nscd being overwritten with corrupt data through the stack overflow, until the buggy code path eventually results in a crash. Finally, a crash in nscd may result in performance degradation when resolving names, but it does not result in a denial of service.
View original CVE JSON
{
"id": "CVE-2026-89092",
"sourceIdentifier": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
"published": "2026-09-11T02:18:35.460",
"lastModified": "2026-10-26T23:10:00.183",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "The nscd service in the GNU C Library 2.3.4 onwards may crash due to a \nstack overflow when a malicious DNS server returns too large a response \nfor a DNS query, resulting in degraded DNS resolution for the system.\n\n\n\nExploitation of this bug needs a system that has nscd enabled and using \nan untrusted DNS server for name resolution, with the compromised DNS \nserver being capable of processing records large enough to result in a \nstack overflow in an nscd thread stack. During experimentation, bind 9 \nwas unable to handle large records, but that could change in future or \nwith a different name server. In typical installations, nscd is \nexecuted in an isolated context as its own user without a shell, due to \nwhich any compromise of that service is isolated.\n\n\n\nThere is a remote possibility of nscd cache corruption if an attacker \nmanages to get the stack pointer into a desired point in the heap, \npotentially resulting in other caches in nscd being overwritten with \ncorrupt data through the stack overflow, until the buggy code path \neventually results in a crash.\n\n\n\nFinally, a crash in nscd may result in performance degradation when \nresolving names, but it does not result in a denial of service."
},
{
"lang": "es",
"value": "El servicio nscd en la Biblioteca C de GNU a partir de la versión 2.3.4 puede fallar debido a un desbordamiento de pila cuando un servidor DNS malicioso devuelve una respuesta demasiado grande para una consulta DNS, lo que provoca una degradación de la resolución DNS del sistema.\\n\\nExplotar este error requiere un sistema que tenga nscd habilitado y que utilice un servidor DNS no confiable para la resolución de nombres, con el servidor DNS comprometido capaz de procesar registros lo suficientemente grandes como para generar un desbordamiento de pila en la pila de un hilo de nscd. Durante la experimentación, bind 9 no pudo manejar registros grandes, pero eso podría cambiar en el futuro o con un servidor de nombres diferente. En instalaciones típicas, nscd se ejecuta en un contexto aislado como su propio usuario sin shell, por lo que cualquier compromiso de ese servicio queda aislado.\\n\\nExiste una posibilidad remota de corrupción de la caché de nscd si un atacante logra colocar el puntero de pila en un punto deseado del montículo, lo que podría resultar en que otras cachés en nscd sean sobrescritas con datos corruptos mediante el desbordamiento de pila, hasta que la ruta de código defectuosa finalmente provoque un fallo.\\n\\nFinalmente, un fallo en nscd puede provocar una degradación del rendimiento al resolver nombres, pero no genera una denegación de servicio."
}
],
"affected": [
{
"source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
"affectedData": [
{
"vendor": "The GNU C Library",
"product": "glibc",
"defaultStatus": "unaffected",
"versions": [
{
"version": "2.3.4",
"lessThan": "2.45",
"versionType": "custom",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L",
"baseScore": 4.2,
"baseSeverity": "MEDIUM",
"attackVector": "ADJACENT_NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"availabilityImpact": "LOW"
},
"exploitabilityScore": 1.6,
"impactScore": 2.5
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-09-11T16:57:22.665457Z",
"id": "CVE-2026-89092",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-789"
}
]
}
],
"references": [
{
"url": "https://sourceware.org/bugzilla/show_bug.cgi?id=34624",
"source": "3ff69d7a-14f2-4f67-a097-88dee7810d18"
},
{
"url": "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0016",
"source": "3ff69d7a-14f2-4f67-a097-88dee7810d18"
},
{
"url": "http://www.openwall.com/lists/oss-security/2026/09/11/2",
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
]
}