Source: https://thekelleys.org.uk/dnsmasq.git
MR: 110238
Type: Security Fix
Disposition: Backport from https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=74d4fcd756a85bc1823232ea74334f7ccfb9d5d2


ChangeID: 3365bcc47b0467b487f14fc6bfad89bc560cd818
Description:

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.
Signed-off-by: Armin Kuster <akuster@mvista.com>