Cisco is warning of a new critical zero-day IOS / IOS XE vulnerability that affects more than 300 of its switch models.

The company identified this highest level of vulnerability in its product while analysing the Vault 7 leak, 8,761 documents and files leaked by Wikileaks last week, claiming to detail hacking tools and tactics of the Central Intelligence Agency (CIA).

The vulnerability resides in the Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software.

If exploited, the flaw (CVE-2017-3881) could allow an unauthenticated, remote attacker to cause a reboot of an affected device or remotely execute malicious code on the device with elevated privileges to take full control of the device, Cisco says in its advisory.

How to fix it? As there is no patch we would recommend disabling the telnet port as soon as possible.

Check your Cisco product/version on their website.