CVE-2001-1548: Zonelabs Zonealarm

Low severity, CVSS 2.1. EPSS: 0.4% chance of exploitation in the next 30 days.

ZoneAlarm 2.1 through 2.6 and ZoneAlarm Pro 2.4 and 2.6 allows local users to bypass filtering via non-standard TCP packets created with non-Windows protocol adapters.

Affected products

• Zonelabs Zonealarm: version 2.1 only; version 2.2 only; version 2.3 only; version 2.4 only; version 2.5 only; version 2.6 only

Published 2001-12-31. Last modified 2026-06-16.