1. Ubuntu Security Notices
  2. USN-4976-1

USN-4976-1: Dnsmasq vulnerability

Publication date

2 June 2021

Overview

Dnsmasq could be exposed to cache poisoning.

Releases

Packages

  • dnsmasq - Small caching DNS proxy and DHCP/TFTP server

Details

Petr Mensik discovered that Dnsmasq incorrectly randomized source ports in
certain configurations. A remote attacker could possibly use this issue to
facilitate DNS cache poisoning attacks.

Petr Mensik discovered that Dnsmasq incorrectly randomized source ports in
certain configurations. A remote attacker could possibly use this issue to
facilitate DNS cache poisoning attacks.

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
21.04 hirsute dnsmasq –  2.84-1ubuntu2.1
dnsmasq-utils –  2.84-1ubuntu2.1
dnsmasq-base –  2.84-1ubuntu2.1
20.10 groovy dnsmasq –  2.82-1ubuntu1.3
dnsmasq-utils –  2.82-1ubuntu1.3
dnsmasq-base –  2.82-1ubuntu1.3
20.04 focal dnsmasq –  2.80-1.1ubuntu1.4
dnsmasq-utils –  2.80-1.1ubuntu1.4
dnsmasq-base –  2.80-1.1ubuntu1.4
18.04 bionic dnsmasq –  2.79-1ubuntu0.4
dnsmasq-utils –  2.79-1ubuntu0.4
dnsmasq-base –  2.79-1ubuntu0.4

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Get Ubuntu Pro

References

Have additional questions?

Talk to a member of the team ›