net-snmp before 5.8.1.pre1 has a double free in usm_free_usmStateReference in snmplib/snmpusm.c via an SNMPv3 GetBulk request. NOTE: this affects net-snmp packages shipped to end users by multiple Linux distributions, but might not affect an upstream release. CREATE(Triage):(User=admin) CVE-2019-20892 (https://nvd.nist.gov/vuln/detail/CVE-2019-20892)