CVE-2025-20140: Cisco IOS XE

High severity, CVSS 7.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A vulnerability in the Wireless Network Control daemon (wncd) of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent wireless attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper memory management. An attacker could exploit this vulnerability by sending a series of IPv6 network requests from an associated wireless IPv6 client to an affected device. To associate a client to a device, an attacker may first need to authenticate to the network, or associate freely in the case of a configured open network. A successful exploit could allow the attacker to cause the wncd process to consume available memory and eventually cause the device to stop responding, resulting in a DoS condition.

Affected products

• Cisco IOS XE: version 16.4.1 only; version 16.4.2 only; version 16.4.3 only; version 16.5.1 only; version 16.5.1a only; version 16.5.1b only; …

Published 2025-05-07. Last modified 2026-06-17.