CVE-2026-20308: Cisco IOS XE Software

Medium severity, CVSS 4.3. 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 perform a denial of service (DoS) attack against an affected device. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted input to the web-based management interface of an affected device. A successful exploit could allow the attacker to cause the web-based management interface to become unresponsive.

Affected products

• Cisco Cisco IOS XE Software: version 17.2.1a only; version 16.12.1y only; version 16.12.3s only; version 16.12.1w only; version 16.9.1d only; version 17.3.1 only; …

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