UBUNTU-CVE-2026-77860

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Source

https://ubuntu.com/security/CVE-2026-77860

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77860.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-77860

Upstream

CVE-2026-77860

Published

2026-09-17T00:00:00Z

Modified

2026-09-17T13:30:13Z

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 NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb (CVE-2024-33655). A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice. This second query was named 'pump'. By alternating slow queries and pumps, the attacker keeps the per-client counter at or below the configured 'wait-limit' indefinitely, and can hold an arbitrary number of pending queries from a single source IP, up to the global mesh quota (num-queries-per-thread); eventually bypassing one of the counter measures introduced for DNSBomb (CVE-2024-33655). This vulnerability is present on the 'serve-expired' code path.

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-2026-77860.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-2026-77860.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-2026-77860.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-2026-77860.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-2026-77860.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-2026-77860.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-2026-77860.json"