Ubuntu: USN-7239-1 (CVE-2020-6080): libmicrodns vulnerabilities

An exploitable denial-of-service vulnerability exists in the resource allocation handling of Videolabs libmicrodns 0.1.0. When encountering errors while parsing mDNS messages, some allocated data is not freed, possibly leading to a denial-of-service condition via resource exhaustion. An attacker can send one mDNS message repeatedly to trigger this vulnerability through the function rr_read_RR [5] reads the current resource record, except for the RDATA section. This is read by the loop at in rr_read. For each RR type, a different function is called. When the RR type is 0x10, the function rr_read_TXT is called at [6].