CVE-2026-81563
Full vulnerability record from the local CVENow database.
Description
A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
Published
2026-09-16 14:17:10.543000
Last modified
2026-10-26 20:10:00.160000
View original CVE JSON
{
"id": "CVE-2026-81563",
"sourceIdentifier": "[email protected]",
"published": "2026-09-16T14:17:10.543",
"lastModified": "2026-10-26T20:10:00.160",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups.\nThis issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1."
},
{
"lang": "es",
"value": "Un resolvedor BIND que encuentre un registro SVCB/HTTPS AliasMode que haga referencia a 14 o más registros SVCB/HTTPS ServiceMode puede no liberar correctamente los recursos internos. Si esto ocurre repetidamente, el agotamiento de recursos impedirá eventualmente que el resolvedor realice nuevas búsquedas recursivas. \\nEste problema afecta a BIND?9 desde la versión?9.18.0 hasta la versión?9.18.50 incluida, desde la versión?9.20.0 hasta la versión?9.20.27 incluida, desde la versión?9.21.0 hasta la versión?9.21.25 incluida, desde la versión?9.18.11?S1 hasta la versión?9.18.50?S1 incluida, y desde la versión?9.20.9?S1 hasta la versión?9.20.27?S1 incluida."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "ISC",
"product": "BIND 9",
"defaultStatus": "unaffected",
"versions": [
{
"version": "9.18.0",
"lessThanOrEqual": "9.18.50",
"versionType": "custom",
"status": "affected"
},
{
"version": "9.20.0",
"lessThanOrEqual": "9.20.27",
"versionType": "custom",
"status": "affected"
},
{
"version": "9.21.0",
"lessThanOrEqual": "9.21.25",
"versionType": "custom",
"status": "affected"
},
{
"version": "9.18.11-S1",
"lessThanOrEqual": "9.18.50-S1",
"versionType": "custom",
"status": "affected"
},
{
"version": "9.20.9-S1",
"lessThanOrEqual": "9.20.27-S1",
"versionType": "custom",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-09-17T17:47:13.244761Z",
"id": "CVE-2026-81563",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-401"
}
]
}
],
"references": [
{
"url": "https://downloads.isc.org/isc/bind9/9.20.29",
"source": "[email protected]"
},
{
"url": "https://downloads.isc.org/isc/bind9/9.21.26",
"source": "[email protected]"
},
{
"url": "https://kb.isc.org/docs/cve-2026-81563",
"source": "[email protected]"
}
]
}