A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "binary_version": "2.75-1ubuntu0.16.04.7", "binary_name": "dnsmasq" }, { "binary_version": "2.75-1ubuntu0.16.04.7", "binary_name": "dnsmasq-base" }, { "binary_version": "2.75-1ubuntu0.16.04.7", "binary_name": "dnsmasq-utils" } ] }
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "binary_version": "2.79-1ubuntu0.2", "binary_name": "dnsmasq" }, { "binary_version": "2.79-1ubuntu0.2", "binary_name": "dnsmasq-base" }, { "binary_version": "2.79-1ubuntu0.2", "binary_name": "dnsmasq-base-lua" }, { "binary_version": "2.79-1ubuntu0.2", "binary_name": "dnsmasq-utils" } ] }
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "binary_version": "2.80-1.1ubuntu1.2", "binary_name": "dnsmasq" }, { "binary_version": "2.80-1.1ubuntu1.2", "binary_name": "dnsmasq-base" }, { "binary_version": "2.80-1.1ubuntu1.2", "binary_name": "dnsmasq-base-lua" }, { "binary_version": "2.80-1.1ubuntu1.2", "binary_name": "dnsmasq-utils" } ] }