bind9 — security advisory
In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.
- Products
- bind9
- Affected versions
- Not specified
- Fixed versions
- 1:9.17.19-1
- CVEs
- CVE-2021-25219
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 00:05 UTC · Revision 1
Source evidence
In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.
osv:DEBIAN-CVE-2021-25219
bind9
Fixed versions: 1:9.17.19-1
bind9
Fixed versions: 1:9.17.19-1
bind9
Fixed versions: 1:9.17.19-1
Complete source record
{
"id": "713e193eec57b12cb8345f4c8bd1fbcd43ffb58b977e01c8ea512eecc0f824f1",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-25219",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-25219",
"summary": "In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.",
"evidence": "osv:DEBIAN-CVE-2021-25219",
"products": [
{
"name": {
"value": "bind9",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:9.17.19-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "bind9",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:9.17.19-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "bind9",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:9.17.19-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2021-25219",
"aliases": [
"DEBIAN-CVE-2021-25219"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:9.17.19-1"
}
]
}
],
"package": {
"name": "bind9",
"purl": "pkg:deb/debian/bind9?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-25219.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:9.17.19-1"
}
]
}
],
"package": {
"name": "bind9",
"purl": "pkg:deb/debian/bind9?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-25219.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:9.17.19-1"
}
]
}
],
"package": {
"name": "bind9",
"purl": "pkg:deb/debian/bind9?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-25219.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:02:57.585816923Z",
"provider": "osv",
"upstream": [
"CVE-2021-25219"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-25219"
]
},
"related_cves": [
{
"value": "CVE-2021-25219",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 419914,
"published_at": "2021-10-27T21:15:07.613+00:00"
}