CVE-2020-3226: Cisco IOS

High severity, CVSS 8.6. EPSS: 1.6% chance of exploitation in the next 30 days.

A vulnerability in the Session Initiation Protocol (SIP) library of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient sanity checks on received SIP messages. An attacker could exploit this vulnerability by sending crafted SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service condition.

Affected products

• Cisco IOS: version 15.0(2)sg11a only; version 15.3(3)jaa1 only; version 15.3(3)jpi only; version 15.3(3)jpj only; version 15.3(3)m only; version 15.3(3)m1 only; …
• Cisco IOS XE: version 3.10.0s only; version 3.10.1s only; version 3.10.2as only; version 3.10.2s only; version 3.10.2ts only; version 3.10.3s only; …

Published 2020-06-03. Last modified 2026-06-17.