CVE-2020-25682

8.1 HIGH
Published: January 20, 2021 Modified: November 04, 2025

Description

A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1882014
Source: secalert@redhat.com
Issue Tracking Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
Source: secalert@redhat.com
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202101-17
Source: secalert@redhat.com
Third Party Advisory
https://www.debian.org/security/2021/dsa-4844
Source: secalert@redhat.com
Third Party Advisory
https://www.jsof-tech.com/disclosures/dnspooq/
Source: secalert@redhat.com
Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1882014
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202101-17
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.debian.org/security/2021/dsa-4844
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.jsof-tech.com/disclosures/dnspooq/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.kb.cert.org/vuls/id/434904
Source: af854a3a-2127-422b-91ae-364da2661108

15 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.1 / 10.0
EPSS (Exploit Probability)
34.3%
97th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

debian thekelleys fedoraproject