snmp_oid_compare in snmplib/snmp_api.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be used by an unauthenticated attacker to remotely cause the instance to crash via a crafted UDP packet, resulting in Denial of Service.
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
https://sourceforge.net/p/net-snmp/code/ci/f23bcd3ac6ddee5d0a48f9703007ccc738914791/
https://sourceforge.net/p/net-snmp/code/ci/7ffb8e25a0db851953155de91f0170e9bf8c457d/