UBUNTU-CVE-2020-25687

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Source
https://ubuntu.com/security/CVE-2020-25687
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-25687.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2020-25687
Upstream
Downstream
Related
Published
2021-01-19T00:00:00Z
Modified
2025-08-11T04:41:27Z
Severity
  • 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

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extractname(), which could be abused to make the code execute memcpy() with a negative size in sortrrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

References

Affected packages

Ubuntu:16.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.75-1ubuntu0.16.04.7?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.75-1ubuntu0.16.04.7

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.75-1ubuntu0.16.04.7",
            "binary_name": "dnsmasq"
        },
        {
            "binary_version": "2.75-1ubuntu0.16.04.7",
            "binary_name": "dnsmasq-base"
        },
        {
            "binary_version": "2.75-1ubuntu0.16.04.7",
            "binary_name": "dnsmasq-utils"
        }
    ],
    "availability": "No subscription required"
}

Ubuntu:18.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.79-1ubuntu0.2?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.79-1ubuntu0.2

Affected versions

2.*

2.78-1
2.78-3
2.79-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.79-1ubuntu0.2",
            "binary_name": "dnsmasq"
        },
        {
            "binary_version": "2.79-1ubuntu0.2",
            "binary_name": "dnsmasq-base"
        },
        {
            "binary_version": "2.79-1ubuntu0.2",
            "binary_name": "dnsmasq-base-lua"
        },
        {
            "binary_version": "2.79-1ubuntu0.2",
            "binary_name": "dnsmasq-utils"
        }
    ],
    "availability": "No subscription required"
}

Ubuntu:20.04:LTS / dnsmasq

Package

Name
dnsmasq
Purl
pkg:deb/ubuntu/dnsmasq@2.80-1.1ubuntu1.2?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.80-1.1ubuntu1.2

Affected versions

2.*

2.80-1ubuntu2
2.80-1ubuntu4
2.80-1.1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.80-1.1ubuntu1.2",
            "binary_name": "dnsmasq"
        },
        {
            "binary_version": "2.80-1.1ubuntu1.2",
            "binary_name": "dnsmasq-base"
        },
        {
            "binary_version": "2.80-1.1ubuntu1.2",
            "binary_name": "dnsmasq-base-lua"
        },
        {
            "binary_version": "2.80-1.1ubuntu1.2",
            "binary_name": "dnsmasq-utils"
        }
    ],
    "availability": "No subscription required"
}