Cisco Security Advisory
Cisco Webex Meeting Client Join Certificate Validation Vulnerability
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CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N/E:X/RL:X/RC:X
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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.
As mentioned, Cisco has addressed this vulnerability in the Cisco Webex Meetings service, and no customer action is necessary to update on-premises software or devices. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-join-yNXfqHk4
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Vulnerable Products
This vulnerability affected Cisco Webex Meetings, which is cloud based.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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There are no workarounds that address this vulnerability.
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Cisco has addressed this vulnerability in Cisco Webex Meetings, which is cloud based. No user action is required.
Customers who need additional information are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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Cisco would like to thank the following people for reporting this vulnerability:
- Martin Bach of Technical University of Darmstadt (TU Darmstadt) and Technology Innovation Institute (TII)
- Vukašin Karad?ic of TU Darmstadt
- Lukas Knittel of Ruhr University Bochum
- Robert Merget of TII
- Jean Paul Degabriele of TII
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2025-AUG-06
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