A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. 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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade dnsmasqUpgrade dnsmasq-utils | May 4, 2022 | Jan 20, 2021 |
| Alpine Linux | — | Upgrade dnsmasq | Aug 22, 2024 | Jan 20, 2021 |
| Amazon Linux Ami 2 | — | Upgrade dnsmasq-debuginfoUpgrade dnsmasq-utilsUpgrade dnsmasq | Jan 27, 2021 | Jan 20, 2021 |
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | Jan 20, 2021 |
| Arista Eos | — | Upgrade to a remediated EOS version | Sep 4, 2024 | Jan 19, 2021 |
| Centos_linux | — | Upgrade dnsmasqUpgrade dnsmasq-debugsourceUpgrade dnsmasq-debuginfoUpgrade dnsmasq-utils-debuginfoUpgrade dnsmasq-utils | Jan 20, 2021 | Jan 19, 2021 |
| Debian | — | Upgrade dnsmasq | Feb 4, 2021 | Jan 20, 2021 |
| Freebsd | — | Upgrade dnsmasqUpgrade dnsmasq-devel | Jan 21, 2021 | Jan 20, 2021 |
| Gentoo Linux | — | Upgrade net-dns/dnsmasq. | Jan 25, 2021 | Jan 20, 2021 |
| Huawei Euleros 2_0_sp2 | — | Upgrade dnsmasq-utilsUpgrade dnsmasq | Feb 22, 2021 | Jan 20, 2021 |
| Huawei Euleros 2_0_sp3 | — | Upgrade dnsmasqUpgrade dnsmasq-utils | Feb 22, 2021 | Jan 20, 2021 |
| Huawei Euleros 2_0_sp5 | — | Upgrade dnsmasqUpgrade dnsmasq-utils | Mar 24, 2021 | Jan 20, 2021 |
| Huawei Euleros 2_0_sp8 | — | Upgrade dnsmasqUpgrade dnsmasq-utils | Feb 2, 2021 | Jan 20, 2021 |
| Huawei Euleros 2_0_sp9 | — | Upgrade dnsmasq | Feb 8, 2021 | Jan 20, 2021 |
| Nutanix Ahv | — | Upgrade Nutanix AHV to the latest version | Jun 5, 2026 | Aug 24, 2022 |
| Oracle Solaris | — | Upgrade service/network/dnsmasq to version 2.84-11.4.31.0.1.88.1 on Solaris 11.4 | Mar 17, 2021 | Jan 20, 2021 |
| Oracle_linux | — | Upgrade dnsmasq-utilsUpgrade dnsmasq | Jan 20, 2021 | Jan 19, 2021 |
| Qnap Qts | — | Upgrade QNAP QTS to the latest version | Aug 4, 2025 | Jul 1, 2021 |
| Redhat Openshift | — | Upgrade redhat-coreos | Mar 12, 2021 | Jan 20, 2021 |
| Redhat_linux | — | Upgrade dnsmasqNo solution existsUpgrade dnsmasq-utils-debuginfoUpgrade dnsmasq-utilsUpgrade dnsmasq-debuginfoUpgrade dnsmasq-debugsource | Jan 20, 2021 | Jan 19, 2021 |
| Suse | — | Upgrade dnsmasqUpgrade dnsmasq-utils | Jan 21, 2021 | Jan 19, 2021 |
| Ubuntu | — | Upgrade dnsmasqUpgrade dnsmasq-utilsUpgrade dnsmasq-base | Jan 20, 2021 | Jan 19, 2021 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Jan 20, 2021 |
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