UBUNTU-CVE-2026-85501

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Source

https://ubuntu.com/security/CVE-2026-85501

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85501.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-85501

Upstream

CVE-2026-85501

Published

2026-09-17T00:00:00Z

Modified

2026-09-17T13:30:17Z

Severity

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

Novel vulnerabilities to launch algorithmic complexity attacks on DNSSEC have been researched under the term 'ReTrap'. These result in degradation of service when malicious zones are used to serve the algorithmic complexity vulnerabilities. NLnet Labs Unbound up to and including 1.26.0 is vulnerable to some of them. TagTrap, where the triple(Zone, Algo, KeyTag) matching mechanism introduces a significant attack vector when resolvers handle malicious responses containing numerous mismatched DNSKEY, RRSIG, and DS record. DelegationTrap, where constructing the chain-of-trust requires iterative validation of DNSKEY and DS records from the root zone downward. For deeply nested domains, this results in significant computational overhead. NsecTrap, where responses with excessive invalid NSEC records compel the resolver to validate each one. AdditionalTrap, where Unbound by default would try to DNSSEC validate the ADDITIONAL section as well. This can be exploited to waste validation resources by malicious users.

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

0 Unknown 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-2026-85501.json"

Ubuntu:24.04:LTS

unbound

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown 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

1.19.2-1ubuntu3.9

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libunbound8",
            "binary_version": "1.19.2-1ubuntu3.9"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.19.2-1ubuntu3.9"
        },
        {
            "binary_name": "unbound",
            "binary_version": "1.19.2-1ubuntu3.9"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.19.2-1ubuntu3.9"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.19.2-1ubuntu3.9"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85501.json"

Ubuntu:26.04:LTS

unbound

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown 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

1.24.2-1ubuntu2.2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libunbound8",
            "binary_version": "1.24.2-1ubuntu2.2"
        },
        {
            "binary_name": "python3-unbound",
            "binary_version": "1.24.2-1ubuntu2.2"
        },
        {
            "binary_name": "unbound",
            "binary_version": "1.24.2-1ubuntu2.2"
        },
        {
            "binary_name": "unbound-anchor",
            "binary_version": "1.24.2-1ubuntu2.2"
        },
        {
            "binary_name": "unbound-host",
            "binary_version": "1.24.2-1ubuntu2.2"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-85501.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

0 Unknown 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-2026-85501.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

0 Unknown 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-2026-85501.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

0 Unknown 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-2026-85501.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

0 Unknown 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-2026-85501.json"