USN-4976-1: Dnsmasq vulnerability

Releases

• Ubuntu 21.04
• Ubuntu 20.10
• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM

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.

Update instructions

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

Ubuntu 21.04

• dnsmasq - 2.84-1ubuntu2.1
• dnsmasq-utils - 2.84-1ubuntu2.1
• dnsmasq-base - 2.84-1ubuntu2.1

Ubuntu 20.10

• dnsmasq - 2.82-1ubuntu1.3
• dnsmasq-utils - 2.82-1ubuntu1.3
• dnsmasq-base - 2.82-1ubuntu1.3

Ubuntu 20.04

• dnsmasq - 2.80-1.1ubuntu1.4
• dnsmasq-utils - 2.80-1.1ubuntu1.4
• dnsmasq-base - 2.80-1.1ubuntu1.4

Ubuntu 18.04

• dnsmasq - 2.79-1ubuntu0.4
• dnsmasq-utils - 2.79-1ubuntu0.4
• dnsmasq-base - 2.79-1ubuntu0.4

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

References

• CVE-2021-3448

Related notices

• USN-4976-2: dnsmasq, dnsmasq-base, dnsmasq-base-lua, dnsmasq-utils