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GHSA-HH5G-G7M5-5VXV

Vulnerability from github – Published: 2026-04-15 18:31 – Updated: 2026-04-15 18:31

Details

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.

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-20184"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-15T17:17:03Z",
    "severity": "CRITICAL"
  },
  "details": "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.\n\nThis 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.",
  "id": "GHSA-hh5g-g7m5-5vxv",
  "modified": "2026-04-15T18:31:58Z",
  "published": "2026-04-15T18:31:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20184"
    },
    {
      "type": "WEB",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-20184 (GCVE-0-2026-20184)

Vulnerability from cvelistv5 – Published: 2026-04-15 16:03 – Updated: 2026-04-16 19:07

Title

Cisco Webex Meetings Certificate Validation Vulnerability

Summary

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.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-15 00:00 UTC

CWE

CWE-295 - Improper Certificate Validation

Assigner

cisco mitre root

References

1 reference

URL	Tags
https://sec.cloudapps.cisco.com/security/center/c…

Impacted products

1 product

Vendor	Product	Version
Cisco	Cisco Webex Meetings	Affected: 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

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-20184",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-15T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
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          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-16T03:55:32.095Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Cisco Webex Meetings",
          "vendor": "Cisco",
          "versions": [
            {
              "status": "affected",
              "version": "39.7.7"
            },
            {
              "status": "affected",
              "version": "39.9"
            },
            {
              "status": "affected",
              "version": "40.4.10"
            },
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              "status": "affected",
              "version": "39.6"
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              "status": "affected",
              "version": "40.6.2"
            },
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              "status": "affected",
              "version": "39.8.2"
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              "version": "39.8.4"
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              "status": "affected",
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              "status": "affected",
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              "status": "affected",
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            },
            {
              "status": "affected",
              "version": "39.7"
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              "status": "affected",
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            {
              "status": "affected",
              "version": "39.8.3"
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              "status": "affected",
              "version": "40.2"
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              "status": "affected",
              "version": "42.7"
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              "version": "42.8"
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            {
              "status": "affected",
              "version": "42.9"
            },
            {
              "status": "affected",
              "version": "42.10"
            },
            {
              "status": "affected",
              "version": "42.11"
            },
            {
              "status": "affected",
              "version": "42.12"
            },
            {
              "status": "affected",
              "version": "43.1"
            },
            {
              "status": "affected",
              "version": "43.2"
            },
            {
              "status": "affected",
              "version": "43.3"
            },
            {
              "status": "affected",
              "version": "43.4"
            },
            {
              "status": "affected",
              "version": "43.4.1"
            },
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              "status": "affected",
              "version": "43.4.2"
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              "status": "affected",
              "version": "43.5.0"
            },
            {
              "status": "affected",
              "version": "43.6.0"
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            {
              "status": "affected",
              "version": "43.6.1"
            },
            {
              "status": "affected",
              "version": "43.7"
            },
            {
              "status": "affected",
              "version": "43.8"
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              "status": "affected",
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              "status": "affected",
              "version": "43.10"
            },
            {
              "status": "affected",
              "version": "43.11"
            },
            {
              "status": "affected",
              "version": "43.12"
            },
            {
              "status": "affected",
              "version": "44.1"
            },
            {
              "status": "affected",
              "version": "44.2"
            },
            {
              "status": "affected",
              "version": "44.3"
            },
            {
              "status": "affected",
              "version": "44.4"
            },
            {
              "status": "affected",
              "version": "44.5"
            },
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              "status": "affected",
              "version": "44.6"
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            {
              "status": "affected",
              "version": "44.7"
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              "status": "affected",
              "version": "44.8"
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              "status": "affected",
              "version": "44.9"
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              "status": "affected",
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              "version": "44.11"
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              "status": "affected",
              "version": "45.1"
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              "status": "affected",
              "version": "45.2"
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              "status": "affected",
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          "lang": "en",
          "value": "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.\r\n\r\nThis 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."
        }
      ],
      "exploits": [
        {
          "lang": "en",
          "value": "The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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      "problemTypes": [
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          "descriptions": [
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              "description": "Improper Certificate Validation",
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      "providerMetadata": {
        "dateUpdated": "2026-04-16T19:07:14.461Z",
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      },
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        {
          "name": "cisco-sa-webex-cui-cert-8jSZYhWL",
          "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL"
        }
      ],
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        "advisory": "cisco-sa-webex-cui-cert-8jSZYhWL",
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      },
      "title": "Cisco Webex Meetings Certificate Validation Vulnerability"
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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-HH5G-G7M5-5VXV

CVE-2026-20184 (GCVE-0-2026-20184)

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