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
Upstream
Released (2.83)
Ubuntu 21.04 (Hirsute Hippo)
Released (2.82-1ubuntu2)
Ubuntu 20.10 (Groovy Gorilla)
Released (2.82-1ubuntu1.1)
Ubuntu 20.04 LTS (Focal Fossa)
Released (2.80-1.1ubuntu1.2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (2.79-1ubuntu0.2)
Ubuntu 16.04 LTS (Xenial Xerus)
Released (2.75-1ubuntu0.16.04.7)
Ubuntu 14.04 ESM (Trusty Tahr) Needs triage