Please be advised that Cisco announced the following medium impact security vulnerability.

A vulnerability in the meeting-join functionality of Cisco Webex Meetings could have allowed an unauthenticated, network-proximate attacker to complete a meeting-join process in place of an intended targeted user, provided the requisite conditions were satisfied. Cisco has addressed this vulnerability in the Cisco Webex Meetings service, and no customer action is needed.

This vulnerability existed due to client certificate validation issues. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by monitoring local wireless or adjacent networks for client-join requests and attempting to interrupt and complete the meeting-join flow as another user who was currently joining a meeting. To successfully exploit the vulnerability, an attacker would need the capability to position themselves in a local wireless or adjacent network, to monitor and intercept the targeted network traffic flows, and to satisfy timing requirements in order to interrupt the meeting-join flow and exploit the vulnerability. A successful exploit could have allowed the attacker to join the meeting as another user. However, the Cisco Product Security Incident Response Team (PSIRT) is not aware of any malicious use of the vulnerability that is described in this advisory.

There are no workarounds that address this vulnerability.

Full description of the vulnerability is available on the following link:

Cisco Webex Meeting Client Join Certificate Validation Vulnerability

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• Vulnerable products

This vulnerability affected Cisco Webex Meetings, which is cloud based.

• Fixed Software

Cisco has addressed this vulnerability in Cisco Webex Meetings, which is cloud based. No user action is required. The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.