CVE-2000-0380: Cisco IOS

High severity, CVSS 7.1. EPSS: 35% chance of exploitation in the next 30 days.

The IOS HTTP service in Cisco routers and switches running IOS 11.1 through 12.1 allows remote attackers to cause a denial of service by requesting a URL that contains a %% string.

Affected products

• Cisco IOS: version 11.1 only; version 11.2 only; version 11.2(4)f1 only; version 11.2(8) only; version 11.2(8)p only; version 11.2(9)p only; …

Published 2000-04-26. Last modified 2026-06-16.