CVE-2026-20311: Cisco IOS XE Software

Medium severity, CVSS 6.3. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in the web-based management interface. An attacker could exploit this vulnerability by authenticating with a malformed certificate. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Affected products

• Cisco Cisco IOS XE Software: version 17.3.1 only; version 17.3.1a only; version 17.3.2a only; version 17.3.1w only; version 17.3.2 only; version 17.4.1 only; …

Published 2026-08-05. Last modified 2026-08-06.