Cisco AsyncOS before 8.5.7-043, 9.x before 9.1.1-023, and 9.5.x and 9.6.x before 9.6.0-046 on Email Security Appliance (ESA) devices mishandles malformed fields during body-contains, attachment-contains, every-attachment-contains, attachment-binary-contains, dictionary-match, and attachment-dictionary-match filtering, which allows remote attackers to cause a denial of service (memory consumption) via a crafted attachment in an e-mail message, aka Bug ID CSCuv47151.