CVE-2017-3818: Cisco Email Security Appliance Firmware

Medium severity, CVSS 5.8. EPSS: 2.2% chance of exploitation in the next 30 days.

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device, aka a Malformed MIME Header Filtering Bypass. 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. More Information: CSCvb65245. Known Affected Releases: 9.7.1-066. Known Fixed Releases: 9.8.0-092.

Affected products

• Cisco Email Security Appliance Firmware: version 9.7.1-066 only

Published 2017-02-03. Last modified 2026-06-17.