CVE-2026-20184

Cisco Webex Meetings Certificate Validation Vulnerability

Published Apr 15, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Description

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Webex Meetings

unknown

Version	Status	Constraints
`39.7.7`	affected	—
`39.9`	affected	—
`40.4.10`	affected	—
`39.6`	affected	—
`40.6.2`	affected	—
`39.8.2`	affected	—
`39.8.4`	affected	—
`40.1`	affected	—
`39.11`	affected	—
`39.7.4`	affected	—
`39.9.1`	affected	—
`40.4`	affected	—
`40.6`	affected	—
`39.7`	affected	—
`39.8`	affected	—
`39.8.3`	affected	—
`40.2`	affected	—
`39.10`	affected	—
`42.6`	affected	—
`42.7`	affected	—
`42.8`	affected	—
`42.9`	affected	—
`42.10`	affected	—
`42.11`	affected	—
`42.12`	affected	—
`43.1`	affected	—
`43.2`	affected	—
`43.3`	affected	—
`43.4`	affected	—
`43.4.1`	affected	—
`43.4.2`	affected	—
`43.5.0`	affected	—
`43.6.0`	affected	—
`43.6.1`	affected	—
`43.7`	affected	—
`43.8`	affected	—
`43.9`	affected	—
`43.10`	affected	—
`43.11`	affected	—
`43.12`	affected	—
`44.1`	affected	—
`44.2`	affected	—
`44.3`	affected	—
`44.4`	affected	—
`44.5`	affected	—
`44.6`	affected	—
`44.7`	affected	—
`44.8`	affected	—
`44.9`	affected	—
`44.10`	affected	—
`44.11`	affected	—
`44.12`	affected	—
`45.1`	affected	—
`45.2`	affected	—
`45.3`	affected	—
`45.4`	affected	—

No data.

Vendor Product Versions

Cisco

Webex Meetings

Version	Status	Scheme	Platform
`39.7.7`	affected	semver	—
`39.9`	affected	generic	—
`40.4.10`	affected	semver	—
`39.6`	affected	generic	—
`40.6.2`	affected	semver	—
`39.8.2`	affected	semver	—
`39.8.4`	affected	semver	—
`40.1`	affected	generic	—
`39.11`	affected	generic	—
`39.7.4`	affected	semver	—
`39.9.1`	affected	semver	—
`40.4`	affected	generic	—
`40.6`	affected	generic	—
`39.7`	affected	generic	—
`39.8`	affected	generic	—
`39.8.3`	affected	semver	—
`40.2`	affected	generic	—
`39.10`	affected	generic	—
`42.6`	affected	generic	—
`42.7`	affected	generic	—
`42.8`	affected	generic	—
`42.9`	affected	generic	—
`42.10`	affected	generic	—
`42.11`	affected	generic	—
`42.12`	affected	generic	—
`43.1`	affected	generic	—
`43.2`	affected	generic	—
`43.3`	affected	generic	—
`43.4`	affected	generic	—
`43.4.1`	affected	semver	—
`43.4.2`	affected	semver	—
`43.5.0`	affected	semver	—
`43.6.0`	affected	semver	—
`43.6.1`	affected	semver	—
`43.7`	affected	generic	—
`43.8`	affected	generic	—
`43.9`	affected	generic	—
`43.10`	affected	generic	—
`43.11`	affected	generic	—
`43.12`	affected	generic	—
`44.1`	affected	generic	—
`44.2`	affected	generic	—
`44.3`	affected	generic	—
`44.4`	affected	generic	—
`44.5`	affected	generic	—
`44.6`	affected	generic	—
`44.7`	affected	generic	—
`44.8`	affected	generic	—
`44.9`	affected	generic	—
`44.10`	affected	generic	—
`44.11`	affected	generic	—
`44.12`	affected	generic	—
`45.1`	affected	generic	—
`45.2`	affected	generic	—
`45.3`	affected	generic	—
`45.4`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.529% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact total

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL

History

Apr 16, 2026 9:30 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco webex Meetings
Vendors & Products		Cisco Cisco webex Meetings

Apr 15, 2026 5:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Apr 15, 2026 4:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Cisco Webex Meetings Certificate Validation Vulnerability
Weaknesses		CWE-295
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL
Metrics		cvssV3_1 `{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`