CVE-2020-25686

Publication date 19 January 2021

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

3.7 · Low

Score breakdown

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.

Status

Package Ubuntu Release Status
dnsmasq 24.10 oracular
Fixed 2.82-1ubuntu2
24.04 LTS noble
Fixed 2.82-1ubuntu2
23.10 mantic
Fixed 2.82-1ubuntu2
23.04 lunar
Fixed 2.82-1ubuntu2
22.10 kinetic
Fixed 2.82-1ubuntu2
22.04 LTS jammy
Fixed 2.82-1ubuntu2
21.10 impish
Fixed 2.82-1ubuntu2
21.04 hirsute
Fixed 2.82-1ubuntu2
20.10 groovy
Fixed 2.82-1ubuntu1.1
20.04 LTS focal
Fixed 2.80-1.1ubuntu1.2
18.04 LTS bionic
Fixed 2.79-1ubuntu0.2
16.04 LTS xenial
Fixed 2.75-1ubuntu0.16.04.7
14.04 LTS trusty Ignored end of ESM support, was needs-triage

Severity score breakdown

Parameter Value
Base score 3.7 · Low
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact Low
Availability impact None
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N