CVE-2021-3448

NameCVE-2021-3448
DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
dnsmasq (PTS)stretch2.76-5+deb9u2vulnerable
stretch (security)2.76-5+deb9u3vulnerable
buster, buster (security)2.80-1+deb10u1vulnerable
bookworm, bullseye2.85-1fixed
sid2.86-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
dnsmasqsource(unstable)2.85-1

Notes

[buster] - dnsmasq <postponed> (Revisit once upstream has backported to 2.80)
[stretch] - dnsmasq <postponed> (Probably easier to base the patch on a backported version)
https://bugzilla.redhat.com/show_bug.cgi?id=1939368
https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=74d4fcd756a85bc1823232ea74334f7ccfb9d5d2

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