HighFix available
unbound — security advisory
In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.
- Products
- unbound
- Affected versions
- 1.13.1-1ubuntu1, 1.13.1-1ubuntu3, 1.13.1-1ubuntu5, 1.13.1-1ubuntu5.1, 1.13.1-1ubuntu5.10, 1.13.1-1ubuntu5.11, 1.13.1-1ubuntu5.12, 1.13.1-1ubuntu5.13, 1.13.1-1ubuntu5.14, 1.13.1-1ubuntu5.15, 1.13.1-1ubuntu5.16, 1.13.1-1ubuntu5.2, 1.13.1-1ubuntu5.3, 1.13.1-1ubuntu5.4, 1.13.1-1ubuntu5.5, 1.13.1-1ubuntu5.7, 1.13.1-1ubuntu5.8, 1.17.1-2, 1.18.0-2ubuntu1, 1.18.0-2ubuntu2, 1.19.1-1ubuntu1, 1.19.2-1ubuntu1, 1.19.2-1ubuntu3, 1.19.2-1ubuntu3.1, 1.19.2-1ubuntu3.10, 1.19.2-1ubuntu3.2, 1.19.2-1ubuntu3.3, 1.19.2-1ubuntu3.4, 1.19.2-1ubuntu3.5, 1.19.2-1ubuntu3.6, 1.19.2-1ubuntu3.7, 1.19.2-1ubuntu3.8, 1.19.2-1ubuntu3.9, 1.22.0-2ubuntu2, 1.22.0-2ubuntu4, 1.24.2-1ubuntu1, 1.24.2-1ubuntu2, 1.24.2-1ubuntu2.1, 1.24.2-1ubuntu2.2, 1.24.2-1ubuntu2.3, 1.25.1-1ubuntu1, 1.25.1-1ubuntu3, 1.9.0-2ubuntu1, 1.9.0-2ubuntu2, 1.9.4-2, 1.9.4-2ubuntu1, 1.9.4-2ubuntu1.1, 1.9.4-2ubuntu1.11, 1.9.4-2ubuntu1.11+esm1, 1.9.4-2ubuntu1.11+esm2, 1.9.4-2ubuntu1.2, 1.9.4-2ubuntu1.3, 1.9.4-2ubuntu1.4, 1.9.4-2ubuntu1.5, 1.9.4-2ubuntu1.6, 1.9.4-2ubuntu1.8, 1.9.4-2ubuntu1.9
- Fixed versions
- 1.13.1-1ubuntu5.17, 1.19.2-1ubuntu3.12, 1.24.2-1ubuntu2.4, 1.9.4-2ubuntu1.11+esm3
- CVEs
- CVE-2026-80225
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 16:38 UTC · Revision 1
Source evidence
In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.
osv:UBUNTU-CVE-2026-80225
unbound
Fixed versions: 1.9.4-2ubuntu1.11+esm3
unbound
Fixed versions: 1.13.1-1ubuntu5.17
unbound
Fixed versions: 1.19.2-1ubuntu3.12
unbound
Fixed versions: Not specified
unbound
Fixed versions: 1.24.2-1ubuntu2.4
Complete source record
{
"id": "9e2970b3fc09edc26a3a17560ee41989888b37ad5c7397e897f9a99ce367ac0f",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-80225",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-80225",
"summary": "In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.",
"evidence": "osv:UBUNTU-CVE-2026-80225",
"products": [
{
"name": {
"value": "unbound",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.9.4-2ubuntu1.11+esm3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "1.9.0-2ubuntu1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.0-2ubuntu2",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.2",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.3",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.4",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.5",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.6",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.8",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.9",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.11",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.11+esm1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4-2ubuntu1.11+esm2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.13.1-1ubuntu5.17",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "1.13.1-1ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu3",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.1",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.2",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.3",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.4",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.5",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.7",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.8",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.10",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.11",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.12",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.13",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.14",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.15",
"evidence": "/affected/1/versions"
},
{
"value": "1.13.1-1ubuntu5.16",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.19.2-1ubuntu3.12",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "1.17.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.18.0-2ubuntu1",
"evidence": "/affected/2/versions"
},
{
"value": "1.18.0-2ubuntu2",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.1-1ubuntu1",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu1",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.1",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.2",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.3",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.4",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.5",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.6",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.7",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.8",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.9",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.2-1ubuntu3.10",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.24.2-1ubuntu2",
"evidence": "/affected/3/versions"
},
{
"value": "1.25.1-1ubuntu1",
"evidence": "/affected/3/versions"
},
{
"value": "1.25.1-1ubuntu3",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.24.2-1ubuntu2.4",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": [
{
"value": "1.22.0-2ubuntu2",
"evidence": "/affected/4/versions"
},
{
"value": "1.22.0-2ubuntu4",
"evidence": "/affected/4/versions"
},
{
"value": "1.24.2-1ubuntu1",
"evidence": "/affected/4/versions"
},
{
"value": "1.24.2-1ubuntu2",
"evidence": "/affected/4/versions"
},
{
"value": "1.24.2-1ubuntu2.1",
"evidence": "/affected/4/versions"
},
{
"value": "1.24.2-1ubuntu2.2",
"evidence": "/affected/4/versions"
},
{
"value": "1.24.2-1ubuntu2.3",
"evidence": "/affected/4/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-80225",
"aliases": [
"UBUNTU-CVE-2026-80225"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.9.4-2ubuntu1.11+esm3"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra%2Ffocal",
"ecosystem": "Ubuntu:Pro:20.04:LTS"
},
"versions": [
"1.9.0-2ubuntu1",
"1.9.0-2ubuntu2",
"1.9.4-2",
"1.9.4-2ubuntu1",
"1.9.4-2ubuntu1.1",
"1.9.4-2ubuntu1.2",
"1.9.4-2ubuntu1.3",
"1.9.4-2ubuntu1.4",
"1.9.4-2ubuntu1.5",
"1.9.4-2ubuntu1.6",
"1.9.4-2ubuntu1.8",
"1.9.4-2ubuntu1.9",
"1.9.4-2ubuntu1.11",
"1.9.4-2ubuntu1.11+esm1",
"1.9.4-2ubuntu1.11+esm2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80225.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libunbound8",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
},
{
"binary_name": "python-unbound",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
},
{
"binary_name": "python3-unbound",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
},
{
"binary_name": "unbound",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
},
{
"binary_name": "unbound-anchor",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
},
{
"binary_name": "unbound-host",
"binary_version": "1.9.4-2ubuntu1.11+esm3"
}
],
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.13.1-1ubuntu5.17"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/ubuntu/unbound?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"1.13.1-1ubuntu1",
"1.13.1-1ubuntu3",
"1.13.1-1ubuntu5",
"1.13.1-1ubuntu5.1",
"1.13.1-1ubuntu5.2",
"1.13.1-1ubuntu5.3",
"1.13.1-1ubuntu5.4",
"1.13.1-1ubuntu5.5",
"1.13.1-1ubuntu5.7",
"1.13.1-1ubuntu5.8",
"1.13.1-1ubuntu5.10",
"1.13.1-1ubuntu5.11",
"1.13.1-1ubuntu5.12",
"1.13.1-1ubuntu5.13",
"1.13.1-1ubuntu5.14",
"1.13.1-1ubuntu5.15",
"1.13.1-1ubuntu5.16"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80225.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libunbound8",
"binary_version": "1.13.1-1ubuntu5.17"
},
{
"binary_name": "python3-unbound",
"binary_version": "1.13.1-1ubuntu5.17"
},
{
"binary_name": "unbound",
"binary_version": "1.13.1-1ubuntu5.17"
},
{
"binary_name": "unbound-anchor",
"binary_version": "1.13.1-1ubuntu5.17"
},
{
"binary_name": "unbound-host",
"binary_version": "1.13.1-1ubuntu5.17"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.19.2-1ubuntu3.12"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/ubuntu/unbound?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"1.17.1-2",
"1.18.0-2ubuntu1",
"1.18.0-2ubuntu2",
"1.19.1-1ubuntu1",
"1.19.2-1ubuntu1",
"1.19.2-1ubuntu3",
"1.19.2-1ubuntu3.1",
"1.19.2-1ubuntu3.2",
"1.19.2-1ubuntu3.3",
"1.19.2-1ubuntu3.4",
"1.19.2-1ubuntu3.5",
"1.19.2-1ubuntu3.6",
"1.19.2-1ubuntu3.7",
"1.19.2-1ubuntu3.8",
"1.19.2-1ubuntu3.9",
"1.19.2-1ubuntu3.10"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80225.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libunbound8",
"binary_version": "1.19.2-1ubuntu3.12"
},
{
"binary_name": "python3-unbound",
"binary_version": "1.19.2-1ubuntu3.12"
},
{
"binary_name": "unbound",
"binary_version": "1.19.2-1ubuntu3.12"
},
{
"binary_name": "unbound-anchor",
"binary_version": "1.19.2-1ubuntu3.12"
},
{
"binary_name": "unbound-host",
"binary_version": "1.19.2-1ubuntu3.12"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/ubuntu/unbound?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"1.24.2-1ubuntu2",
"1.25.1-1ubuntu1",
"1.25.1-1ubuntu3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80225.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libunbound8",
"binary_version": "1.25.1-1ubuntu3"
},
{
"binary_name": "python3-unbound",
"binary_version": "1.25.1-1ubuntu3"
},
{
"binary_name": "unbound",
"binary_version": "1.25.1-1ubuntu3"
},
{
"binary_name": "unbound-anchor",
"binary_version": "1.25.1-1ubuntu3"
},
{
"binary_name": "unbound-host",
"binary_version": "1.25.1-1ubuntu3"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.24.2-1ubuntu2.4"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/ubuntu/unbound?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.22.0-2ubuntu2",
"1.22.0-2ubuntu4",
"1.24.2-1ubuntu1",
"1.24.2-1ubuntu2",
"1.24.2-1ubuntu2.1",
"1.24.2-1ubuntu2.2",
"1.24.2-1ubuntu2.3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80225.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libunbound8",
"binary_version": "1.24.2-1ubuntu2.4"
},
{
"binary_name": "python3-unbound",
"binary_version": "1.24.2-1ubuntu2.4"
},
{
"binary_name": "unbound",
"binary_version": "1.24.2-1ubuntu2.4"
},
{
"binary_name": "unbound-anchor",
"binary_version": "1.24.2-1ubuntu2.4"
},
{
"binary_name": "unbound-host",
"binary_version": "1.24.2-1ubuntu2.4"
}
],
"availability": "No subscription required"
}
}
],
"modified": "2026-10-21T23:02:21.463975127Z",
"provider": "osv",
"upstream": [
"CVE-2026-80225"
],
"references": [
"https://ubuntu.com/security/CVE-2026-80225",
"https://www.cve.org/CVERecord?id=CVE-2026-80225",
"https://nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt",
"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt",
"https://ubuntu.com/security/notices/USN-8946-1"
]
},
"related_cves": [
{
"value": "CVE-2026-80225",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 401068,
"published_at": "2026-09-16T09:17:00+00:00"
}