UBUNTU-CVE-2026-5947

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Source
https://ubuntu.com/security/CVE-2026-5947
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5947.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-5947
Upstream
Downstream
Related
Published
2026-05-20T00:00:00Z
Modified
2026-05-29T10:45:35.821426011Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.

References

Affected packages

Ubuntu:20.04:LTS / bind9-libs

Package

Name
bind9-libs
Purl
pkg:deb/ubuntu/bind9-libs?arch=source&distro=focal

Affected ranges

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

Affected versions

1:9.*
1:9.11.16+dfsg-3~build1
1:9.11.16+dfsg-3~ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libbind9-161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libdns-export1109",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libdns1109",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libirs-export161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libirs161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisc-export1105",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisc1105",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisccc-export161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisccc161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisccfg-export163",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "libisccfg163",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        },
        {
            "binary_name": "liblwres161",
            "binary_version": "1:9.11.16+dfsg-3~ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5947.json"

Ubuntu:22.04:LTS / bind9-libs

Package

Name
bind9-libs
Purl
pkg:deb/ubuntu/bind9-libs?arch=source&distro=jammy

Affected ranges

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

Affected versions

1:9.*
1:9.11.19+dfsg-2.1ubuntu1
1:9.11.19+dfsg-2.1ubuntu2
1:9.11.19+dfsg-2.1ubuntu3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libbind9-161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libdns-export1110",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libdns1110",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libirs-export161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libirs161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisc-export1105",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisc1105",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisccc-export161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisccc161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisccfg-export163",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "libisccfg163",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        },
        {
            "binary_name": "liblwres161",
            "binary_version": "1:9.11.19+dfsg-2.1ubuntu3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5947.json"

Ubuntu:25.10 / bind9

Package

Name
bind9
Purl
pkg:deb/ubuntu/bind9?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:9.20.11-1ubuntu2.4

Affected versions

1:9.*
1:9.20.4-3ubuntu1
1:9.20.4-3ubuntu2
1:9.20.4-3ubuntu3
1:9.20.9-2ubuntu1
1:9.20.10-1ubuntu1
1:9.20.11-1ubuntu1
1:9.20.11-1ubuntu2
1:9.20.11-1ubuntu2.1
1:9.20.11-1ubuntu2.2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "bind9",
            "binary_version": "1:9.20.11-1ubuntu2.4"
        },
        {
            "binary_name": "bind9-dnsutils",
            "binary_version": "1:9.20.11-1ubuntu2.4"
        },
        {
            "binary_name": "bind9-host",
            "binary_version": "1:9.20.11-1ubuntu2.4"
        },
        {
            "binary_name": "bind9-libs",
            "binary_version": "1:9.20.11-1ubuntu2.4"
        },
        {
            "binary_name": "bind9-utils",
            "binary_version": "1:9.20.11-1ubuntu2.4"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5947.json"

Ubuntu:26.04:LTS / bind9

Package

Name
bind9
Purl
pkg:deb/ubuntu/bind9?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:9.20.18-1ubuntu2.1

Affected versions

1:9.*
1:9.20.11-1ubuntu2
1:9.20.11-1ubuntu3
1:9.20.18-1ubuntu1
1:9.20.18-1ubuntu2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "bind9",
            "binary_version": "1:9.20.18-1ubuntu2.1"
        },
        {
            "binary_name": "bind9-dnsutils",
            "binary_version": "1:9.20.18-1ubuntu2.1"
        },
        {
            "binary_name": "bind9-host",
            "binary_version": "1:9.20.18-1ubuntu2.1"
        },
        {
            "binary_name": "bind9-libs",
            "binary_version": "1:9.20.18-1ubuntu2.1"
        },
        {
            "binary_name": "bind9-utils",
            "binary_version": "1:9.20.18-1ubuntu2.1"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5947.json"