CVE-2026-20301

Name of the Vulnerable Software and Affected Versions Cisco IOS Software (affected versions not specified) Cisco IOS XE Software (affected versions not specified)

Description An issue in the Extensible Messaging Client Protocol (XMCP), also known as the External Client protocol, allows an unauthenticated remote attacker to trigger a denial of service (DoS) condition. The flaw stems from the improper handling of malformed XMCP packets. By sending such a packet to an affected device, an attacker can cause the system to reload unexpectedly. This action does not require the XMCP client username.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.