CVE-2003-1109: Cisco IOS

High severity, CVSS 7.5. EPSS: 6.8% chance of exploitation in the next 30 days.

The Session Initiation Protocol (SIP) implementation in multiple Cisco products including IP Phone models 7940 and 7960, IOS versions in the 12.2 train, and Secure PIX 5.2.9 to 6.2.2 allows remote attackers to cause a denial of service and possibly execute arbitrary code via crafted INVITE messages, as demonstrated by the OUSPG PROTOS c07-sip test suite.

Affected products

• Cisco IOS: version 12.2(1)xa only; version 12.2(1)xd only; version 12.2(1)xd1 only; version 12.2(1)xd3 only; version 12.2(1)xd4 only; version 12.2(1)xe only; …
• Cisco IP Phone 7940: any version
• Cisco IP Phone 7960: any version
• Cisco Pix Firewall Software: version 5.2(1) only; version 5.2(2) only; version 5.2(3.210) only; version 5.2(5) only; version 5.2(6) only; version 5.2(7) only; …

Published 2003-12-31. Last modified 2026-06-16.