CVE-2007-2688: Cisco IOS

High severity, CVSS 7.8. EPSS: 3% chance of exploitation in the next 30 days.

The Cisco Intrusion Prevention System (IPS) and IOS with Firewall/IPS Feature Set do not properly handle certain full-width and half-width Unicode character encodings, which might allow remote attackers to evade detection of HTTP traffic.

Affected products

• Cisco IOS: version 10.0 only; version 11.1cc only; version 11.3 only; version 12.0 only; version 12.0s only; version 12.0st only; …
• Cisco Ips Sensor Software: version 4.0 only; version 5.0(1) only; version 5.0(2) only; version 5.0(6)p1 only; version 5.1(1) only; version 5.1(1a) only; …

Published 2007-05-16. Last modified 2026-06-16.