Cisco Webex Services Vulnerability Let Remote Attacker Impersonate Any User

Cisco published a critical advisory for CVE-2026-20184 (CVSS 9.8) affecting Webex Services SSO: improper certificate validation in the SSO implementation (CWE-295) can allow unauthenticated remote attackers to bypass authentication and impersonate users. Cisco applied a backend patch but administrators must manually upload new SAML certificates in Webex Control Hub to remediate; no evidence of in-the-wild exploitation at the time of publication.