CVE-2020-25686

3.7 LOW
Published: January 20, 2021 Modified: November 04, 2025

Description

A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

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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:N/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1890125
Source: secalert@redhat.com
Issue Tracking Patch 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=1890125
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Patch 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
3.7 / 10.0
EPSS (Exploit Probability)
0.5%
63th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

arista debian fedoraproject thekelleys