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.
The net-snmp package in OpenBSD through 5.8 uses 0644 permissions for snmpd.conf, which allows local users to obtain sensitive community information by reading this file.