CVE-2021-3448: Fedoraproject Fedora

Medium severity, CVSS 4.0. EPSS: 2.3% chance of exploitation in the next 30 days.

A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

Affected products

• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Oracle Communications Cloud Native Core Network Function Cloud Native Environment: version 1.9.0 only
• Red Hat Enterprise Linux: version 8.0 only
• Thekelleys Dnsmasq: before 2.85 (fixed in 2.85)

Published 2021-04-08. Last modified 2026-06-17.