CVE-2016-6458: Cisco Email Security Appliance Firmware

High severity, CVSS 7.5. EPSS: 2.2% chance of exploitation in the next 30 days.

A vulnerability in the content filtering functionality of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to bypass content filters configured on an affected device. Email that should have been filtered could instead be forwarded by the device. 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 use a content filter for email attachments that are protected or encrypted. More Information: CSCva52546. Known Affected Releases: 10.0.0-125 9.7.1-066.

Affected products

• Cisco Email Security Appliance Firmware: version 9.7.1-066 only; version 9.7.2-046 only; version 9.7.2-047 only; version 9.7.2-054 only; version 9.9.6-026 only; version 9.9_base only; …

Published 2016-11-19. Last modified 2026-06-17.