Authentication Bypass Affecting dnsmasq package, versions <0:2.76-16.el7_9.1


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.62% (80th percentile)

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  • Snyk IDSNYK-CENTOS7-DNSMASQ-2180124
  • published26 Jul 2021
  • disclosed19 Jan 2021

Introduced: 19 Jan 2021

CVE-2020-25686  (opens in a new tab)
CWE-290  (opens in a new tab)

How to fix?

Upgrade Centos:7 dnsmasq to version 0:2.76-16.el7_9.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dnsmasq package and not the dnsmasq package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

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.

CVSS Scores

version 3.1