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CVE-2020-25687

Published: 19 January 2021

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Priority

Medium

CVSS 3 base score: 5.9

Status

Package Release Status
dnsmasq
Launchpad, Ubuntu, Debian
bionic
Released (2.79-1ubuntu0.2)
focal
Released (2.80-1.1ubuntu1.2)
groovy
Released (2.82-1ubuntu1.1)
hirsute
Released (2.82-1ubuntu2)
impish
Released (2.82-1ubuntu2)
jammy
Released (2.82-1ubuntu2)
precise Ignored
(end of ESM support, was needs-triage)
trusty Needs triage

upstream
Released (2.83)
xenial
Released (2.75-1ubuntu0.16.04.7)