A heap-based buffer overflow was discovered in dnsmasq before version 2.83 when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rtc1035.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.
A heap-based buffer overflow was discovered in dnsmasq before version 2.83 when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rtc1035.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.
https://www.openwall.com/lists/oss-security/2021/01/19/1 https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2021q1/014599.html https://www.jsof-tech.com/disclosures/dnspooq/ https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=4e96a4be685c9e4445f6ee79ad0b36b9119b502a
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