CVE-2020-3596: Cisco Expressway

High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days.

A vulnerability in the Session Initiation Protocol (SIP) of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to incorrect handling of incoming SIP traffic. An attacker could exploit this vulnerability by sending a series of SIP packets to an affected device. A successful exploit could allow the attacker to exhaust memory on an affected device, causing it to crash and leading to a DoS condition.

Affected products

• Cisco Expressway: up to and including x12.6.3
• Cisco Telepresence Video Communication Server: up to and including x12.6.3

Published 2020-10-08. Last modified 2026-06-17.