CVE-2016-6356: Cisco Email Security Appliance

High severity, CVSS 7.5. EPSS: 3% chance of exploitation in the next 30 days.

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to cause an affected device to stop scanning and forwarding email messages due to a denial of service (DoS) condition. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Email Security Appliances, both virtual and hardware appliances, if the software is configured to apply a message filter or content filter to incoming email attachments. The vulnerability is not limited to any specific rules or actions for a message filter or content filter. More Information: CSCuz63143. Known Affected Releases: 8.5.7-042 9.7.0-125. Known Fixed Releases: 10.0.0-125 9.1.1-038 9.7.2-047.

Affected products

• Cisco Email Security Appliance: version 3.3.1-09 only; version 7.1.0 only; version 7.1.1 only; version 7.1.2 only; version 7.1.3 only; version 7.1.4 only; …

Published 2016-10-28. Last modified 2026-06-17.