snmplib/mib.c in net-snmp 5.7.0 and earlier, when the -OQ option is used, allows remote attackers to cause a denial of service (snmptrapd crash) via a crafted SNMP trap message, which triggers a conversion to the variable type designated in the MIB file, as demonstrated by a NULL type in an ifMtu trap message. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-3565