Artifacts
- Token requests with invalid or self-signed certificate signatures.
- Unexpected traffic spikes to Control Hub SSO endpoints.
CVE-2026-20184: Cisco Webex SSO Impersonation Vulnerability
Executive Summary
Section titled “Executive Summary”Analysis shows that a critical vulnerability exists in the integration of SSO with Control Hub in Cisco Webex Services. This flaw allows an unauthenticated, remote attacker to impersonate any user within the service, leading to full account takeover and unauthorized access to protected resources.
Technical Analysis
Section titled “Technical Analysis”The vulnerability is rooted in improper certificate validation, classified under CWE-295. Cisco systems failed to properly verify the authenticity of certificates during the SSO token exchange process within the Control Hub integration.
Exploit Vector
Section titled “Exploit Vector”The attack surface is exposed via the SSO service endpoint. By providing a crafted token to this endpoint, an attacker can bypass authentication mechanisms.
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8 (CRITICAL)
Forensic Artifacts and Detection
Section titled “Forensic Artifacts and Detection”Organizations should monitor logs for anomalous token requests originating from unauthorized service endpoints.
Detection
- Review Cisco Webex administrative logs for unauthorized impersonation attempts.
- Validate SSO configuration settings against Cisco’s security baselines.
Mitigation
Section titled “Mitigation”- Patch affected Cisco Webex infrastructure immediately.
- Review identity provider configurations to ensure strict certificate validation is enforced.
- Audit SSO logs for any signs of compromise within the identified timeframe.