A vulnerability in Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper management of memory resources, referred to as a double free. An attacker could exploit this vulnerability by sending crafted SNMP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. To exploit this vulnerability via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for an affected system. To exploit this vulnerability via SNMP Version 3, the attacker must know the user credentials for the affected system. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, have been configured to be queried over SNMP, and have Network Address Translation (NAT) enabled. Cisco Bug IDs: CSCve75818.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-snmp-dos