CVE-2001-1183: Cisco IOS

Medium severity, CVSS 5.0. EPSS: 3.8% chance of exploitation in the next 30 days.

PPTP implementation in Cisco IOS 12.1 and 12.2 allows remote attackers to cause a denial of service (crash) via a malformed packet.

Affected products

• Cisco IOS: version 12.1e only; version 12.1ez only; version 12.1t only; version 12.1ya only; version 12.1yc only; version 12.1yd only; …

Published 2001-07-12. Last modified 2026-06-16.