A vulnerability in the email message scanning of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass configured content filters on the device. The vulnerability is due to improper input validation of the email body. An attacker could exploit this vulnerability by inserting specific character strings in the message. A successful exploit could allow the attacker to bypass configured content filters that would normally drop the email.
There are no workarounds that address this vulnerability.
This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-esa-filter-bypass ["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-esa-filter-bypass"]