UBUNTU-CVE-2021-3448

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Source
https://ubuntu.com/security/CVE-2021-3448
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3448.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2021-3448
Upstream
Downstream
Related
Published
2021-04-08T23:15:00Z
Modified
2025-09-08T16:46:43Z
Severity
  • 4.0 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - low
Summary
[none]
Details

A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

References

Affected packages

Ubuntu:Pro:14.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.68-1ubuntu0.2+esm3?arch=source&distro=esm-infra-legacy/trusty

Affected ranges

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

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+esm3"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.68-1ubuntu0.2+esm3"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.68-1ubuntu0.2+esm3"
        }
    ]
}

Ubuntu:Pro:16.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.79-1ubuntu0.16.04.1+esm1?arch=source&distro=esm-infra/xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.79-1ubuntu0.16.04.1+esm1

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

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.79-1ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.79-1ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.79-1ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.79-1ubuntu0.16.04.1+esm1"
        }
    ]
}

Ubuntu:18.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.79-1ubuntu0.4?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.79-1ubuntu0.4

Affected versions

2.*

2.78-1
2.78-3
2.79-1
2.79-1ubuntu0.2
2.79-1ubuntu0.3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.79-1ubuntu0.4"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.79-1ubuntu0.4"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.79-1ubuntu0.4"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.79-1ubuntu0.4"
        }
    ]
}

Ubuntu:20.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.80-1.1ubuntu1.4?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.80-1.1ubuntu1.4

Affected versions

2.*

2.80-1ubuntu2
2.80-1ubuntu4
2.80-1.1ubuntu1
2.80-1.1ubuntu1.2
2.80-1.1ubuntu1.3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "dnsmasq",
            "binary_version": "2.80-1.1ubuntu1.4"
        },
        {
            "binary_name": "dnsmasq-base",
            "binary_version": "2.80-1.1ubuntu1.4"
        },
        {
            "binary_name": "dnsmasq-base-lua",
            "binary_version": "2.80-1.1ubuntu1.4"
        },
        {
            "binary_name": "dnsmasq-utils",
            "binary_version": "2.80-1.1ubuntu1.4"
        }
    ]
}