# CVE-2021-3448: 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. - Web page: https://patchblox.com/security/cve/CVE-2021-3448 - Priority: Routine - CVSS: 4.0 (Low) - EPSS: 0.0228 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 8, 2021 ## Description 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 | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dnsmasq RHEL 8 | 0:2.79-19.el8 | [RHSA-2021:4153](https://patchblox.com/security/data/fix/linux/rhsa-2021-4153.md) | Nov 9, 2021 | | Linux | dnsmasq Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | [dnsmasq 2.79-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-2.79-1ubuntu0.4.md) | Apr 8, 2021 | | Linux | dnsmasq Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | [dnsmasq 2.80-1.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-2.80-1.1ubuntu1.4.md) | Apr 8, 2021 | | Linux | dnsmasq Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | [dnsmasq 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-dnsmasq-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | [dnsmasq 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-dnsmasq-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq almalinux 8 | 2.79-19.el8 | [ALSA-2021:4153](https://patchblox.com/security/data/fix/linux/alsa-2021-4153.md) | Nov 9, 2021 | | Linux | dnsmasq ol 8 | 0:2.79-19.el8 | [ELSA-2021-4153](https://patchblox.com/security/data/fix/linux/elsa-2021-4153.md) | Nov 16, 2021 | | Linux | dnsmasq rocky 8 | 0:2.79-19.el8 | [RLSA-2021:4153](https://patchblox.com/security/data/fix/linux/rlsa-2021-4153.md) | Nov 9, 2021 | | Linux | dnsmasq-base Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | [dnsmasq-base 2.79-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-base-2.79-1ubuntu0.4.md) | Apr 8, 2021 | | Linux | dnsmasq-base Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | [dnsmasq-base 2.80-1.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-base-2.80-1.1ubuntu1.4.md) | Apr 8, 2021 | | Linux | dnsmasq-base Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | [dnsmasq-base 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-dnsmasq-base-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-base Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | [dnsmasq-base 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-dnsmasq-base-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-base-lua Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | [dnsmasq-base-lua 2.79-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-base-lua-2.79-1ubuntu0.4.md) | Apr 8, 2021 | | Linux | dnsmasq-base-lua Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | [dnsmasq-base-lua 2.80-1.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-base-lua-2.80-1.1ubuntu1.4.md) | Apr 8, 2021 | | Linux | dnsmasq-base-lua Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | [dnsmasq-base-lua 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-dnsmasq-base-lua-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-base-lua Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | [dnsmasq-base-lua 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-dnsmasq-base-lua-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-utils RHEL 8 | 0:2.79-19.el8 | [RHSA-2021:4153](https://patchblox.com/security/data/fix/linux/rhsa-2021-4153.md) | Nov 9, 2021 | | Linux | dnsmasq-utils Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.4 | [dnsmasq-utils 2.79-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-dnsmasq-utils-2.79-1ubuntu0.4.md) | Apr 8, 2021 | | Linux | dnsmasq-utils Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.4 | [dnsmasq-utils 2.80-1.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-dnsmasq-utils-2.80-1.1ubuntu1.4.md) | Apr 8, 2021 | | Linux | dnsmasq-utils Ubuntu 24.10 (oracular) | 2.85-1ubuntu1 | [dnsmasq-utils 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-dnsmasq-utils-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-utils Ubuntu 25.04 (plucky) | 2.85-1ubuntu1 | [dnsmasq-utils 2.85-1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-dnsmasq-utils-2.85-1ubuntu1.md) | Jan 16, 2026 | | Linux | dnsmasq-utils almalinux 8 | 2.79-19.el8 | [ALSA-2021:4153](https://patchblox.com/security/data/fix/linux/alsa-2021-4153.md) | Nov 9, 2021 | | Linux | dnsmasq-utils ol 8 | 0:2.79-19.el8 | [ELSA-2021-4153](https://patchblox.com/security/data/fix/linux/elsa-2021-4153.md) | Nov 16, 2021 | --- Data as of 2026-11-08T00:53:09Z UTC. 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