Cisco Webex Services Certificate Validation Vulnerability

A vulnerability in the integration of single sign-on (SSO) with Control Hub in Cisco Webex Services could have allowed an unauthenticated, remote attacker to impersonate any user within the service. This vulnerability existed because of improper certificate validation. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by connecting to a service endpoint and supplying a crafted token. A successful exploit could have allowed the attacker to gain unauthorized access to legitimate Cisco Webex services. Cisco has addressed this vulnerability in the Cisco Webex service. However, customer action is necessary for affected organizations that are using trust anchors with their SSO integration. There are no workarounds that address this vulnerability. To avoid service interruption, customers who are using trust anchors with their SSO integration should upload a new identity provider (IdP) SAML certificate to Control Hub. For more information, see Manage single sign-on integration in Control Hub . This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL Security Impact Rating: Critical CVE: CVE-2026-20184