UBUNTU-CVE-2026-41637

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Source
https://ubuntu.com/security/CVE-2026-41637
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-41637
Upstream
Published
2026-07-22T14:17:00Z
Modified
2026-10-17T12:58:15Z
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 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service for new clients for already in-flight queries. A malicious actor can exploit the vulnerability by issuing DoQ queries for query names that need resolution and proceeding on immediately terminating the query by one of STOP_SENDING/RESET_STREAM/CONNECTION_CLOSE QUIC frames. Those terminated DoQ queries are not properly counted for and keep inflating the number of waiting replies for in-flight queries. When the maximum is reached, it results in silent query drops for new clients needing resolution for already in-flight queries. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces. Additionally, a malicious actor needs access to multiple source IPs to bypass the by-default configured 'wait-limit' option.

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
1.13.1-1ubuntu5.16

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound8",
            "binary_version":  "1.13.1-1ubuntu5.16"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.13.1-1ubuntu5.16"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.13.1-1ubuntu5.16"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.13.1-1ubuntu5.16"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.13.1-1ubuntu5.16"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.19.2-1ubuntu3.10

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound8",
            "binary_version":  "1.19.2-1ubuntu3.10"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.19.2-1ubuntu3.10"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.19.2-1ubuntu3.10"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.19.2-1ubuntu3.10"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.19.2-1ubuntu3.10"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.24.2-1ubuntu2.3

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound8",
            "binary_version":  "1.24.2-1ubuntu2.3"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.24.2-1ubuntu2.3"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.24.2-1ubuntu2.3"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.24.2-1ubuntu2.3"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.24.2-1ubuntu2.3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.json"
Ubuntu:26.10
unbound

Package

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

Affected ranges

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

Affected versions

1.*
1.24.2-1ubuntu2
1.25.1-1ubuntu1
1.25.1-1ubuntu3

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound8",
            "binary_version":  "1.25.1-1ubuntu3"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.25.1-1ubuntu3"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.25.1-1ubuntu3"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.25.1-1ubuntu3"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.25.1-1ubuntu3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.4.22-1ubuntu4.14.04.3+esm4

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound2",
            "binary_version":  "1.4.22-1ubuntu4.14.04.3+esm4"
        },
        {
            "binary_name":  "python-unbound",
            "binary_version":  "1.4.22-1ubuntu4.14.04.3+esm4"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.4.22-1ubuntu4.14.04.3+esm4"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.4.22-1ubuntu4.14.04.3+esm4"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.4.22-1ubuntu4.14.04.3+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.5.8-1ubuntu1.1+esm4

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound2",
            "binary_version":  "1.5.8-1ubuntu1.1+esm4"
        },
        {
            "binary_name":  "python-unbound",
            "binary_version":  "1.5.8-1ubuntu1.1+esm4"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.5.8-1ubuntu1.1+esm4"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.5.8-1ubuntu1.1+esm4"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.5.8-1ubuntu1.1+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.6.7-1ubuntu2.6+esm5

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound2",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        },
        {
            "binary_name":  "python-unbound",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.6.7-1ubuntu2.6+esm5"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.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
1.9.4-2ubuntu1.11+esm2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libunbound8",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        },
        {
            "binary_name":  "python-unbound",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        },
        {
            "binary_name":  "python3-unbound",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        },
        {
            "binary_name":  "unbound",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        },
        {
            "binary_name":  "unbound-anchor",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        },
        {
            "binary_name":  "unbound-host",
            "binary_version":  "1.9.4-2ubuntu1.11+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-41637.json"