CVE-2020-3200: Cisco IOS

High severity, CVSS 7.7. EPSS: 1.7% chance of exploitation in the next 30 days.

A vulnerability in the Secure Shell (SSH) server code of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload. The vulnerability is due to an internal state not being represented correctly in the SSH state machine, which leads to an unexpected behavior. An attacker could exploit this vulnerability by creating an SSH connection to an affected device and using a specific traffic pattern that causes an error condition within that connection. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

Affected products

• Cisco IOS: version 12.2(6)i1 only; version 12.2(58)ex only; version 12.2(58)ey only; version 12.2(58)ey1 only; version 12.2(58)ey2 only; version 12.2(58)ez only; …
• Cisco IOS XE: version 3.2.0se only; version 3.2.1se only; version 3.2.2se only; version 3.2.3se only; version 3.3.0se only; version 3.3.0sg only; …

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