CVE-2017-12309: Cisco Email Security Appliance Firmware

Medium severity, CVSS 5.3. EPSS: 1.7% chance of exploitation in the next 30 days.

A vulnerability in the Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to conduct a HTTP response splitting attack. The vulnerability is due to the failure of the application or its environment to properly sanitize input values. An attacker could exploit this vulnerability by injecting malicious HTTP headers, controlling the response body, or splitting the response into multiple responses. An exploit could allow the attacker to perform cross-site scripting attacks, cross-user defacement, web cache poisoning, and similar exploits. Cisco Bug IDs: CSCvf16705.

Affected products

• Cisco Email Security Appliance Firmware: version 10.0.2-020 only; version 11.0.0-105 only

Published 2017-11-16. Last modified 2026-06-17.