CVE-2009-0636: Cisco IOS

High severity, CVSS 7.8. EPSS: 2.9% chance of exploitation in the next 30 days.

Unspecified vulnerability in Cisco IOS 12.0 through 12.4, when SIP voice services are enabled, allows remote attackers to cause a denial of service (device crash) via a valid SIP message.

Affected products

• Cisco IOS: version 12.0 only; version 12.0da only; version 12.0db only; version 12.0dc only; version 12.0s only; version 12.0sc only; …

Published 2009-03-27. Last modified 2026-06-16.