ubuntu-cve-2026-40209
Vulnerability from osv_ubuntu
Published
2026-06-25 13:16
Modified
2026-06-29 21:20
Summary
Details
An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.
Severity
5.3 (Medium)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.0.0~alpha2-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:16.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.0.0~alpha2-1?arch=source\u0026distro=xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0.0~alpha2-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.2.1-1ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.2.1-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.2.0-1",
"1.2.0-3",
"1.2.1-1",
"1.2.1-1build1",
"1.2.1-1ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.4.0-1ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.4.0-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.4.0~rc3-1",
"1.4.0-1",
"1.4.0-1build1",
"1.4.0-1build2",
"1.4.0-1ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.6.1-1ubuntu0.1~esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:22.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.6.1-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.5.1-3build2",
"1.6.1-1build1",
"1.6.1-1ubuntu0.1~esm1",
"1.6.1-1ubuntu0.1~esm2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.8.3-2ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:24.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.8.3-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.8.0-1",
"1.8.2-1",
"1.8.2-2",
"1.8.2-3",
"1.8.3-1",
"1.8.3-2",
"1.8.3-2build1",
"1.8.3-2build2",
"1.8.3-2ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "1.9.10-1ubuntu0.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@1.9.10-1ubuntu0.1?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.9.8-1",
"1.9.10-1",
"1.9.10-1ubuntu0.1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "dnsdist",
"binary_version": "2.0.2-1build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "dnsdist",
"purl": "pkg:deb/ubuntu/dnsdist@2.0.2-1build1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.9.10-1",
"2.0.1-1",
"2.0.2-1",
"2.0.2-1build1"
]
}
],
"aliases": [],
"details": "An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.",
"id": "UBUNTU-CVE-2026-40209",
"modified": "2026-06-29T21:20:03Z",
"published": "2026-06-25T13:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-40209"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-40209"
},
{
"type": "REPORT",
"url": "https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html#cve-2026-40209-denial-of-service-via-ixfr-queries"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-40209"
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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