dnsmasq: A flaw was found in dnsmasq in versions before 2.85
CVE-2021-3448 is fixed in 4 products on 1 platform, first by dnsmasq 2.79-1ubuntu0.4, released April 8, 2021. It is not reported as exploited. Patch Radar priority: Routine.
A flaw was found in dnsmasq in versions before 2.85. When configured to usea specific server for a given network interface, dnsmasq uses a fixed portwhile forwarding queries. An attacker on the network, able to find theoutgoing port used by dnsmasq, only needs to guess the random transmissionID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNSCache Poisoning attack much easier. The highest threat from thisvulnerability is to data integrity.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| dnsmasq · RHEL 8 | 0:2.79-19.el8 | RHSA-2021:4153 | Nov 9, 2021 |
| dnsmasq · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | dnsmasq 2.79-1ubuntu0.4 | Apr 8, 2021 |
| dnsmasq · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | dnsmasq 2.80-1.1ubuntu1.4 | Apr 8, 2021 |
| dnsmasq · Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | dnsmasq 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq · Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | dnsmasq 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq · almalinux 8 | 2.79-19.el8 | ALSA-2021:4153 | Nov 9, 2021 |
| dnsmasq · ol 8 | 0:2.79-19.el8 | ELSA-2021-4153 | Nov 16, 2021 |
| dnsmasq · rocky 8 | 0:2.79-19.el8 | RLSA-2021:4153 | Nov 9, 2021 |
| dnsmasq-base · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | dnsmasq-base 2.79-1ubuntu0.4 | Apr 8, 2021 |
| dnsmasq-base · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | dnsmasq-base 2.80-1.1ubuntu1.4 | Apr 8, 2021 |
| dnsmasq-base · Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | dnsmasq-base 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-base · Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | dnsmasq-base 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-base-lua · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | dnsmasq-base-lua 2.79-1ubuntu0.4 | Apr 8, 2021 |
| dnsmasq-base-lua · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | dnsmasq-base-lua 2.80-1.1ubuntu1.4 | Apr 8, 2021 |
| dnsmasq-base-lua · Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | dnsmasq-base-lua 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-base-lua · Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | dnsmasq-base-lua 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-utils · RHEL 8 | 0:2.79-19.el8 | RHSA-2021:4153 | Nov 9, 2021 |
| dnsmasq-utils · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | dnsmasq-utils 2.79-1ubuntu0.4 | Apr 8, 2021 |
| dnsmasq-utils · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | dnsmasq-utils 2.80-1.1ubuntu1.4 | Apr 8, 2021 |
| dnsmasq-utils · Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | dnsmasq-utils 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-utils · Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | dnsmasq-utils 2.85-1ubuntu1 | Jan 16, 2026 |
| dnsmasq-utils · almalinux 8 | 2.79-19.el8 | ALSA-2021:4153 | Nov 9, 2021 |
| dnsmasq-utils · ol 8 | 0:2.79-19.el8 | ELSA-2021-4153 | Nov 16, 2021 |
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