Double free vulnerability in Cisco IOS XE 3.15S, 3.16S, and 3.17S allows remote authenticated users to cause a denial of service (device restart) via a sequence of crafted SNMP read requests, aka Bug ID CSCux13174.
http://www.securitytracker.com/id/1036140
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160620-iosxe