CVE-2015-0593: Cisco IOS

High severity, CVSS 7.1. EPSS: 1.5% chance of exploitation in the next 30 days.

The Zone-Based Firewall implementation in Cisco IOS 12.4(122)T and earlier does not properly manage session-object structures, which allows remote attackers to cause a denial of service (device reload) via crafted network traffic, aka Bug ID CSCul65003.

Affected products

• Cisco IOS: version 15.4(1.12)t only; version 15.4(1.19)t only

Published 2015-02-13. Last modified 2026-06-17.