CVE-2026-20184
Improper Certificate Validation in Cisco Webex SSO Enables Impersonation
Publication date: 2026-04-15
Last updated on: 2026-04-15
Assigner: Cisco Systems, Inc.
Description
Description
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| cisco | webex_services | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-295 | The product does not validate, or incorrectly validates, a certificate. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-20184 is a critical vulnerability in Cisco Webex Services involving improper certificate validation in the integration of single sign-on (SSO) with Control Hub.
This flaw allowed an unauthenticated, remote attacker to impersonate any user within the Webex service by connecting to a service endpoint and supplying a crafted token.
Successful exploitation could grant unauthorized access to legitimate Cisco Webex services.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability in Cisco Webex Services allows an unauthenticated, remote attacker to impersonate any user and gain unauthorized access to legitimate services due to improper certificate validation in SSO integration.
Such unauthorized access could potentially lead to exposure or compromise of sensitive personal or protected health information, which may impact compliance with regulations like GDPR and HIPAA that require strict access controls and protection of user data.
Therefore, until the vulnerability is remediated by updating the identity provider SAML certificate and applying Cisco's fixes, affected organizations could be at risk of non-compliance with these standards due to the increased risk of data breaches or unauthorized data access.
How can this vulnerability impact me? :
This vulnerability can have a severe impact as it allows an unauthenticated attacker to impersonate any user within Cisco Webex Services.
- Unauthorized access to legitimate Webex services.
- Potential exposure of sensitive communications and data within the Webex environment.
- Complete compromise of confidentiality, integrity, and availability of affected services, as indicated by the high CVSS score (9.8) with high impact on confidentiality, integrity, and availability.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
There are no specific detection commands or methods provided to identify this vulnerability on your network or system.
The vulnerability involves improper certificate validation in the integration of single sign-on (SSO) with Control Hub in Cisco Webex Services, which is a cloud-based service. Detection would likely require monitoring for unauthorized access attempts or crafted tokens supplied to service endpoints, but no explicit detection commands are given.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, affected customers must upload a new identity provider (IdP) SAML certificate to Control Hub.
Cisco has addressed the vulnerability in the Webex service itself, and no workarounds are available.
Customers requiring assistance are advised to contact Cisco Technical Assistance Center (TAC) or their maintenance providers for guidance.