MediumFix available
unbound — security advisory
With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is registed in the allow list and proceeds to perform the documented cache flush.
- Products
- unbound
- Affected versions
- 1.17.1-2, 1.17.1-2+deb12u1, 1.17.1-2+deb12u2, 1.17.1-2+deb12u3, 1.17.1-2+deb12u4, 1.17.1-2+loong64, 1.18.0-1, 1.18.0-2, 1.19.1-1, 1.19.2-1, 1.20.0-1, 1.21.1-1, 1.22.0-1, 1.22.0-2, 1.22.0-2+deb13u1, 1.22.0-2+deb13u2, 1.22.0-2+deb13u3, 1.23.1-1, 1.24.0-1, 1.24.0-2, 1.24.1-1, 1.24.1-2, 1.24.2-1, 1.25.0-1, 1.25.1-1, 1.25.2-1, 1.26.0-1, 1.26.0-2, 1.26.1-1, 1.26.2-1
- Fixed versions
- 1.25.2-1, 1.26.1-0+deb13u1
- CVEs
- CVE-2026-44621
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 09:56 UTC · Revision 2
Source evidence
With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is registed in the allow list and proceeds to perform the documented cache flush.
osv:DEBIAN-CVE-2026-44621
unbound
Fixed versions: Not specified
unbound
Fixed versions: 1.26.1-0+deb13u1
unbound
Fixed versions: 1.25.2-1
Complete source record
{
"id": "3cf57881041b43d1a4128b731e4f39c113ef9ec5a3637a067c167a878ee48c11",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-44621",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-44621",
"summary": "With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is registed in the allow list and proceeds to perform the documented cache flush.",
"evidence": "osv:DEBIAN-CVE-2026-44621",
"products": [
{
"name": {
"value": "unbound",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.17.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.17.1-2+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1.17.1-2+deb12u2",
"evidence": "/affected/0/versions"
},
{
"value": "1.17.1-2+deb12u3",
"evidence": "/affected/0/versions"
},
{
"value": "1.17.1-2+deb12u4",
"evidence": "/affected/0/versions"
},
{
"value": "1.17.1-2+loong64",
"evidence": "/affected/0/versions"
},
{
"value": "1.18.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.18.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.20.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.21.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.22.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.23.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.24.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.24.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.24.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.24.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.24.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.25.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.25.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.25.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.26.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.26.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.26.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.26.2-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.26.1-0+deb13u1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "1.22.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.0-2+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.0-2+deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "1.22.0-2+deb13u3",
"evidence": "/affected/1/versions"
},
{
"value": "1.23.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.25.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.25.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.25.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.26.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.26.0-2",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "unbound",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.25.2-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "1.22.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.23.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.24.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.24.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.24.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.24.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.24.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.25.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.25.1-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-44621",
"aliases": [
"DEBIAN-CVE-2026-44621"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/debian/unbound?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.17.1-2",
"1.17.1-2+deb12u1",
"1.17.1-2+deb12u2",
"1.17.1-2+deb12u3",
"1.17.1-2+deb12u4",
"1.17.1-2+loong64",
"1.18.0-1",
"1.18.0-2",
"1.19.1-1",
"1.19.2-1",
"1.20.0-1",
"1.21.1-1",
"1.22.0-1",
"1.22.0-2",
"1.23.1-1",
"1.24.0-1",
"1.24.0-2",
"1.24.1-1",
"1.24.1-2",
"1.24.2-1",
"1.25.0-1",
"1.25.1-1",
"1.25.2-1",
"1.26.0-1",
"1.26.0-2",
"1.26.1-1",
"1.26.2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44621.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.26.1-0+deb13u1"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/debian/unbound?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.22.0-2",
"1.22.0-2+deb13u1",
"1.22.0-2+deb13u2",
"1.22.0-2+deb13u3",
"1.23.1-1",
"1.24.0-1",
"1.24.0-2",
"1.24.1-1",
"1.24.1-2",
"1.24.2-1",
"1.25.0-1",
"1.25.1-1",
"1.25.2-1",
"1.26.0-1",
"1.26.0-2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44621.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.25.2-1"
}
]
}
],
"package": {
"name": "unbound",
"purl": "pkg:deb/debian/unbound?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.22.0-2",
"1.23.1-1",
"1.24.0-1",
"1.24.0-2",
"1.24.1-1",
"1.24.1-2",
"1.24.2-1",
"1.25.0-1",
"1.25.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44621.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-25T10:00:55.662168516Z",
"provider": "osv",
"upstream": [
"CVE-2026-44621"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-44621"
]
},
"related_cves": [
{
"value": "CVE-2026-44621",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 445360,
"published_at": "2026-07-22T14:17:18.913+00:00"
}