UBUNTU-CVE-2026-44687

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Source
https://ubuntu.com/security/CVE-2026-44687
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44687.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-44687
Upstream
Published
2026-07-22T14:17:00Z
Modified
2026-07-29T10:18:49.298262473Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

In NLnet Labs Unbound 1.13.2 up to and including 1.25.1, stub or forward zones where the name is below an intermediate labed below a DNSSEC signed zone could be shadowed by the intermediate label's secure NXDOMAIN answer from the parent. This is caused by an off-by-one error in 'harden-below-nxdomain' logic; enabled by default. It effectively bypasses the configuration and the configured stub/forward zone is never contacted. 'harden-below-nxdomain' does an upward DNS cache walk together with a delegation point guard that does not allow NXDOMAIN synthesis above stub/forward zones. The guard tests the domain name but before stripping a label. This results in an iteration where the domain name equals the configured stub/forward zone apex that passes the guard, strips one more label, and probes the cache at the apex's immediate public parent. If that parent has a cached DNSSEC-secure NXDOMAIN, which it will for any private namespace nested two or more labels under a signed public name, the walk returns it and the configured stub/forward upstream is never contacted. This can only be triggered by the query for the intermediate label (between the stub/forward apex and the DNSSEC parent zone).

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

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
1.13.1-1ubuntu5.15

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "libunbound8"
        },
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "python3-unbound"
        },
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "unbound"
        },
        {
            "binary_version": "1.13.1-1ubuntu5.15",
            "binary_name": "unbound-anchor"
        },
        {
            "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-2026-44687.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

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
1.19.2-1ubuntu3.8

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.19.2-1ubuntu3.8",
            "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_name": "unbound-anchor"
        },
        {
            "binary_version": "1.19.2-1ubuntu3.8",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44687.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

Affected versions

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.24.2-1ubuntu2.1",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44687.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_version": "1.4.22-1ubuntu4.14.04.3+esm3",
            "binary_name": "libunbound2"
        },
        {
            "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_version": "1.4.22-1ubuntu4.14.04.3+esm3",
            "binary_name": "unbound-anchor"
        },
        {
            "binary_version": "1.4.22-1ubuntu4.14.04.3+esm3",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44687.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-2026-44687.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_version": "1.6.7-1ubuntu2.6+esm4",
            "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_name": "unbound"
        },
        {
            "binary_version": "1.6.7-1ubuntu2.6+esm4",
            "binary_name": "unbound-anchor"
        },
        {
            "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-2026-44687.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_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "python3-unbound"
        },
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "unbound"
        },
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "unbound-anchor"
        },
        {
            "binary_version": "1.9.4-2ubuntu1.11+esm1",
            "binary_name": "unbound-host"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44687.json"