The uuencode inspection engine in Cisco AsyncOS on Cisco Email Security Appliance (ESA) devices 8.5 and earlier allows remote attackers to bypass intended content restrictions via a crafted e-mail attachment with uuencode encoding, aka Bug ID CSCzv54343.
https://exchange.xforce.ibmcloud.com/vulnerabilities/100695
http://www.securityfocus.com/bid/72528
http://tools.cisco.com/security/center/viewAlert.x?alertId=37384
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2015-0605