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.

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