CVE-2003-0567: Cisco IOS

High severity, CVSS 7.8. EPSS: 16.6% chance of exploitation in the next 30 days.

Cisco IOS 11.x and 12.0 through 12.2 allows remote attackers to cause a denial of service (traffic block) by sending a particular sequence of IPv4 packets to an interface on the device, causing the input queue on that interface to be marked as full.

Affected products

• Cisco IOS: version 11.0 only; version 11.1 only; version 11.1aa only; version 11.1ca only; version 11.1cc only; version 11.2 only; …
• Cisco Ons 15454 Optical Transport Platform: any version
• Cisco Optical Networking Systems Software: version 3.0 only; version 3.1.0 only; version 3.2.0 only; version 3.3.0 only; version 3.4.0 only; version 4.0.0 only

Published 2003-08-18. Last modified 2026-06-16.