UBUNTU-CVE-2026-50243

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Source
https://ubuntu.com/security/CVE-2026-50243
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-50243.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-50243
Upstream
Published
2026-07-22T14:17:00Z
Modified
2026-07-29T10:18:35.822539877Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N CVSS Calculator
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer and can instead rewrite a BOGUS A/AAAA answer to point to an operator's configured IP. If the validator finds an expired or otherwise invalid RRSIG on an answer whose A record falls within a 'response-ip'/RPZ configuration, the answer is still rewritten and given a hard coded security level of INSECURE. This results in the client receiving an INSECURE NOERROR reply rewritten by the operator's configured IP. A malicious actor can exploit the possible poisonous effect by spoofing a BOGUS A/AAAA answer that falls inside the operator's configured subnet rewrites. Such DNSSEC protected answers are then insecurely redirected to the operator's configured target.

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_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",
            "binary_version": "1.13.1-1ubuntu5.15"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-50243.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_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",
            "binary_version": "1.19.2-1ubuntu3.8"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-50243.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_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-2026-50243.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_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",
            "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-2026-50243.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_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",
            "binary_version": "1.5.8-1ubuntu1.1+esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-50243.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_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",
            "binary_version": "1.6.7-1ubuntu2.6+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-50243.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_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",
            "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-2026-50243.json"