CVE-2008-1153: Cisco IOS

High severity, CVSS 7.1. EPSS: 5.6% chance of exploitation in the next 30 days.

Cisco IOS 12.1, 12.2, 12.3, and 12.4, with IPv4 UDP services and the IPv6 protocol enabled, allows remote attackers to cause a denial of service (device crash and possible blocked interface) via a crafted IPv6 packet to the device.

Affected products

• Cisco Cisco IOS: version 12.3 only; version 12.4 only
• Cisco IOS: version 12.1 only; version 12.2 only

Published 2008-03-27. Last modified 2026-06-16.