CVE-2015-4236: Cisco Email Security Appliance

Medium severity, CVSS 4.3. EPSS: 2.4% chance of exploitation in the next 30 days.

Cisco AsyncOS on Email Security Appliance (ESA) devices with software 8.5.6-073, 8.5.6-074, and 9.0.0-461, when clustering is enabled, allows remote attackers to cause a denial of service (clustering and SSH outage) via a packet flood, aka Bug IDs CSCur13704 and CSCuq05636.

Affected products

• Cisco Email Security Appliance: version 8.5.6-074 only
• Cisco Email Security Appliance Firmware: version 8.5.6-073 only; version 9.0.0-461 only

Published 2015-07-10. Last modified 2026-06-17.