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.
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
| Link | Tags |
|---|---|
| https://www.jsof-tech.com/disclosures/dnspooq/ | third party advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=1891568 | patch third party advisory issue tracking |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/ | vendor advisory |
| https://security.gentoo.org/glsa/202101-17 | third party advisory vendor advisory |
| https://www.debian.org/security/2021/dsa-4844 | third party advisory vendor advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/ | vendor advisory |
| https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html | third party advisory mailing list |