UBUNTU-CVE-2026-4893

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Source
https://ubuntu.com/security/CVE-2026-4893
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-4893
Upstream
Downstream
Related
Published
2026-05-11T12:00:00Z
Modified
2026-05-20T16:13:28.022562177Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information.

References

Affected packages

Ubuntu:22.04:LTS
dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.90-0ubuntu0.22.04.3

Affected versions

2.*
2.85-1ubuntu2
2.86-1.1
2.86-1.1ubuntu0.1
2.86-1.1ubuntu0.2
2.86-1.1ubuntu0.3
2.86-1.1ubuntu0.4
2.86-1.1ubuntu0.5
2.90-0ubuntu0.22.04.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.90-0ubuntu0.22.04.3"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.90-0ubuntu0.22.04.3"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.90-0ubuntu0.22.04.3"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.90-0ubuntu0.22.04.3"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:24.04:LTS
dnsmasq

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.90-2ubuntu0.3

Affected versions

2.*
2.89-1
2.90-2
2.90-2build1
2.90-2build2
2.90-2ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.90-2ubuntu0.3"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.90-2ubuntu0.3"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.90-2ubuntu0.3"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.90-2ubuntu0.3"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:25.10
dnsmasq

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.91-1ubuntu0.2

Affected versions

2.*
2.91-1
2.91-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.91-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.91-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.91-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.91-1ubuntu0.2"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:26.04:LTS
dnsmasq

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.92-1ubuntu0.2

Affected versions

2.*
2.91-1build1
2.92~rc3-1
2.92-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.92-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.92-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.92-1ubuntu0.2"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.92-1ubuntu0.2"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:Pro:14.04:LTS
dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.68-1ubuntu0.2+esm5

Affected versions

2.*
2.66-4ubuntu1
2.67-1
2.68-1
2.68-1ubuntu0.1
2.68-1ubuntu0.2
2.68-1ubuntu0.2+esm1
2.68-1ubuntu0.2+esm2
2.68-1ubuntu0.2+esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.68-1ubuntu0.2+esm5"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.68-1ubuntu0.2+esm5"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.68-1ubuntu0.2+esm5"
        }
    ],
    "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:Pro:16.04:LTS
dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq?arch=source&distro=esm-infra%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.90-0ubuntu0.16.04.1+esm3

Affected versions

2.*
2.75-1
2.75-1ubuntu0.16.04.1
2.75-1ubuntu0.16.04.2
2.75-1ubuntu0.16.04.3
2.75-1ubuntu0.16.04.4
2.75-1ubuntu0.16.04.5
2.75-1ubuntu0.16.04.7
2.75-1ubuntu0.16.04.8
2.75-1ubuntu0.16.04.10
2.75-1ubuntu0.16.04.10+esm1
2.79-1ubuntu0.16.04.1+esm1
2.79-1ubuntu0.16.04.1+esm2
2.90-0ubuntu0.16.04.1+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.90-0ubuntu0.16.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.90-0ubuntu0.16.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.90-0ubuntu0.16.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.90-0ubuntu0.16.04.1+esm3"
        }
    ],
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:Pro:18.04:LTS
dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq?arch=source&distro=esm-infra%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.90-0ubuntu0.18.04.1+esm3

Affected versions

2.*
2.78-1
2.78-3
2.79-1
2.79-1ubuntu0.2
2.79-1ubuntu0.3
2.79-1ubuntu0.4
2.79-1ubuntu0.5
2.79-1ubuntu0.6
2.79-1ubuntu0.7
2.90-0ubuntu0.18.04.1+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.90-0ubuntu0.18.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.90-0ubuntu0.18.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.90-0ubuntu0.18.04.1+esm3"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.90-0ubuntu0.18.04.1+esm3"
        }
    ],
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"
Ubuntu:Pro:20.04:LTS
dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq?arch=source&distro=esm-infra%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.90-0ubuntu0.20.04.1+esm2

Affected versions

2.*
2.80-1ubuntu2
2.80-1ubuntu4
2.80-1.1ubuntu1
2.80-1.1ubuntu1.2
2.80-1.1ubuntu1.3
2.80-1.1ubuntu1.4
2.80-1.1ubuntu1.5
2.80-1.1ubuntu1.6
2.80-1.1ubuntu1.7
2.90-0ubuntu0.20.04.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.90-0ubuntu0.20.04.1+esm2"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.90-0ubuntu0.20.04.1+esm2"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.90-0ubuntu0.20.04.1+esm2"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.90-0ubuntu0.20.04.1+esm2"
        }
    ],
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4893.json"