HighFix available
nsd — security advisory
If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes
- Products
- nsd
- Affected versions
- 4.11.1-1, 4.12.0-1, 4.13.0-6, 4.14.0-1, 4.14.2-1, 4.14.3-1, 4.15.0-1, 4.15.0-1build1
- Fixed versions
- 4.14.0-1ubuntu0.1~esm1
- CVEs
- CVE-2026-12244
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:02 UTC · Revision 1
Source evidence
If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes
osv:UBUNTU-CVE-2026-12244
nsd
Fixed versions: Not specified
nsd
Fixed versions: Not specified
nsd
Fixed versions: 4.14.0-1ubuntu0.1~esm1
Complete source record
{
"id": "1aab06d65676768e0514d145f84b5924299ecd4d880f4d41d94add7e56ff74f8",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-12244",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-12244",
"summary": "If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes",
"evidence": "osv:UBUNTU-CVE-2026-12244",
"products": [
{
"name": {
"value": "nsd",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.11.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.12.0-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "nsd",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.14.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.14.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.14.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.15.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.15.0-1build1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "nsd",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.14.0-1ubuntu0.1~esm1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "4.12.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "4.13.0-6",
"evidence": "/affected/2/versions"
},
{
"value": "4.14.0-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-12244",
"aliases": [
"UBUNTU-CVE-2026-12244"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nsd",
"purl": "pkg:deb/ubuntu/nsd?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"4.11.1-1",
"4.12.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-12244.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nsd",
"binary_version": "4.12.0-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nsd",
"purl": "pkg:deb/ubuntu/nsd?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"4.14.0-1",
"4.14.2-1",
"4.14.3-1",
"4.15.0-1",
"4.15.0-1build1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-12244.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nsd",
"binary_version": "4.15.0-1build1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.14.0-1ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "nsd",
"purl": "pkg:deb/ubuntu/nsd?arch=source&distro=esm-apps%2Fresolute",
"ecosystem": "Ubuntu:Pro:26.04:LTS"
},
"versions": [
"4.12.0-1",
"4.13.0-6",
"4.14.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-12244.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nsd",
"binary_version": "4.14.0-1ubuntu0.1~esm1"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
}
],
"modified": "2026-10-17T12:58:04.710255845Z",
"provider": "osv",
"upstream": [
"CVE-2026-12244"
],
"references": [
"https://ubuntu.com/security/CVE-2026-12244",
"https://ubuntu.com/security/notices/USN-8474-1",
"https://www.cve.org/CVERecord?id=CVE-2026-12244"
]
},
"related_cves": [
{
"value": "CVE-2026-12244",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 357963,
"published_at": "2026-06-25T00:00:00+00:00"
}