CVE-2015-6291: Cisco Email Security Appliance

High severity, CVSS 7.8. EPSS: 1.9% chance of exploitation in the next 30 days.

Cisco AsyncOS before 8.5.7-043, 9.x before 9.1.1-023, and 9.5.x and 9.6.x before 9.6.0-046 on Email Security Appliance (ESA) devices mishandles malformed fields during body-contains, attachment-contains, every-attachment-contains, attachment-binary-contains, dictionary-match, and attachment-dictionary-match filtering, which allows remote attackers to cause a denial of service (memory consumption) via a crafted attachment in an e-mail message, aka Bug ID CSCuv47151.

Affected products

• Cisco Email Security Appliance: version 7.7.0-000 only; version 7.7.1-000 only; version 8.0_base only; version 8.5.6-052 only; version 8.5.6-073 only; version 8.5.6-074 only; …

Published 2015-11-06. Last modified 2026-06-17.