UBUNTU-CVE-2026-44390

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Source
https://ubuntu.com/security/CVE-2026-44390
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-44390
Upstream
Downstream
Related
Published
2026-05-20T00:00:00Z
Modified
2026-06-02T20:15:05.949516493Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/U:Amber CVSS Calculator
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very large RRsets with records that don't share a suffix above the root can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. An adversary can exploit the vulnerability by querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. A compression limit was introduced in 1.21.1 for this but it didn't account for the case where records would not share any suffix above the root. That causes Unbound to go in a different code path because of the compression tree lookup failure and eventually not increment the compression counter for those operations. Unbound 1.25.1 contains a patch with a fix that increments the compression counter regardless of the compression tree lookup. This is a complement fix to CVE-2024-8508.

References

Affected packages

Ubuntu:22.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.13.1-1ubuntu5.15

Affected versions

1.*
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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libunbound8",
            "binary_version": "1.13.1-1ubuntu5.15"
        },
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "python3-unbound"
        },
        {
            "binary_name": "unbound",
            "binary_version": "1.13.1-1ubuntu5.15"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.13.1-1ubuntu5.15"
        },
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:24.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.19.2-1ubuntu3.8

Affected versions

1.*
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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libunbound8",
            "binary_version": "1.19.2-1ubuntu3.8"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.19.2-1ubuntu3.8"
        },
        {
            "binary_name": "unbound",
            "binary_version": "1.19.2-1ubuntu3.8"
        },
        {
            "binary_version": "1.19.2-1ubuntu3.8",
            "binary_name": "unbound-anchor"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.19.2-1ubuntu3.8"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:25.10
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.22.0-2ubuntu2.3

Affected versions

1.*
1.22.0-1ubuntu1
1.22.0-2ubuntu1
1.22.0-2ubuntu2
1.22.0-2ubuntu2.1
1.22.0-2ubuntu2.2

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_version": "1.22.0-2ubuntu2.3",
            "binary_name": "libunbound8"
        },
        {
            "binary_version": "1.22.0-2ubuntu2.3",
            "binary_name": "python3-unbound"
        },
        {
            "binary_version": "1.22.0-2ubuntu2.3",
            "binary_name": "unbound"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.22.0-2ubuntu2.3"
        },
        {
            "binary_version": "1.22.0-2ubuntu2.3",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:26.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.24.2-1ubuntu2.1

Affected versions

1.*
1.22.0-2ubuntu2
1.22.0-2ubuntu4
1.24.2-1ubuntu1
1.24.2-1ubuntu2

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libunbound8",
            "binary_version": "1.24.2-1ubuntu2.1"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.24.2-1ubuntu2.1"
        },
        {
            "binary_name": "unbound",
            "binary_version": "1.24.2-1ubuntu2.1"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.24.2-1ubuntu2.1"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.24.2-1ubuntu2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:Pro:14.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.4.20-1
1.4.21-1
1.4.21-1ubuntu1
1.4.21-1ubuntu2
1.4.22-1ubuntu1
1.4.22-1ubuntu2
1.4.22-1ubuntu3
1.4.22-1ubuntu4
1.4.22-1ubuntu4.14.04.1
1.4.22-1ubuntu4.14.04.2
1.4.22-1ubuntu4.14.04.3
1.4.22-1ubuntu4.14.04.3+esm1
1.4.22-1ubuntu4.14.04.3+esm2
1.4.22-1ubuntu4.14.04.3+esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libunbound2",
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3"
        },
        {
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3",
            "binary_name": "python-unbound"
        },
        {
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3",
            "binary_name": "unbound"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:Pro:16.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra-legacy%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.4.22-1ubuntu6
1.5.7-1ubuntu1
1.5.7-1ubuntu2
1.5.8-1ubuntu1
1.5.8-1ubuntu1.1
1.5.8-1ubuntu1.1+esm1
1.5.8-1ubuntu1.1+esm2
1.5.8-1ubuntu1.1+esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.5.8-1ubuntu1.1+esm3",
            "binary_name": "libunbound2"
        },
        {
            "binary_version": "1.5.8-1ubuntu1.1+esm3",
            "binary_name": "python-unbound"
        },
        {
            "binary_version": "1.5.8-1ubuntu1.1+esm3",
            "binary_name": "unbound"
        },
        {
            "binary_version": "1.5.8-1ubuntu1.1+esm3",
            "binary_name": "unbound-anchor"
        },
        {
            "binary_version": "1.5.8-1ubuntu1.1+esm3",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:Pro:18.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.6.5-1
1.6.7-1
1.6.7-1build1
1.6.7-1ubuntu1
1.6.7-1ubuntu2
1.6.7-1ubuntu2.1
1.6.7-1ubuntu2.2
1.6.7-1ubuntu2.3
1.6.7-1ubuntu2.4
1.6.7-1ubuntu2.5
1.6.7-1ubuntu2.6
1.6.7-1ubuntu2.6+esm2
1.6.7-1ubuntu2.6+esm3
1.6.7-1ubuntu2.6+esm4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libunbound2",
            "binary_version": "1.6.7-1ubuntu2.6+esm4"
        },
        {
            "binary_name": "python-unbound",
            "binary_version": "1.6.7-1ubuntu2.6+esm4"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.6.7-1ubuntu2.6+esm4"
        },
        {
            "binary_version": "1.6.7-1ubuntu2.6+esm4",
            "binary_name": "unbound"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.6.7-1ubuntu2.6+esm4"
        },
        {
            "binary_version": "1.6.7-1ubuntu2.6+esm4",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"
Ubuntu:Pro:20.04:LTS
unbound

Package

Name
unbound
Purl
pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "libunbound8"
        },
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "python-unbound"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.9.4-2ubuntu1.11+esm1"
        },
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "unbound"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.9.4-2ubuntu1.11+esm1"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.9.4-2ubuntu1.11+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44390.json"