CISCO-SA-WEBEX-CUI-CERT-8JSZYHWL
Vulnerability from csaf_cisco - Published: 2026-04-15 16:00 - Updated: 2026-04-16 18:52Summary
Cisco Webex Services Certificate Validation Vulnerability
Notes
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.
Cisco has addressed this vulnerability in the Cisco Webex service. However, customer action is necessary for affected organizations that are using trust anchors with their SSO integration.
There are no workarounds that address this vulnerability.
To avoid service interruption, customers who are using trust anchors with their SSO integration should upload a new identity provider (IdP) SAML certificate to Control Hub. For more information, see Manage single sign-on integration in Control Hub ["https://help.webex.com/en-us/article/nstvmyo/Manage-single-sign-on-integration-in-Control-Hub#Cisco_Task_in_List_GUI.dita_07fbdc21-41a0-482f-99dc-b8c17adbd087"].
Vulnerable Products: This vulnerability affected Cisco Webex Services, which are cloud-based, when they were configured to use trust anchors within the SSO integration with Control Hub.
Determine Whether Trust Anchors Are in Use
Only customers who use trust anchors were affected by this vulnerability. To determine whether trust anchors are in use, log in to the Webex Control Hub and verify the SSO configuration.
Products Confirmed Not Vulnerable: Only products listed in the Vulnerable Products ["#vp"] section of this advisory are known to have been affected by this vulnerability.
Workarounds: There are no workarounds that address this vulnerability.
Fixed Software: Cisco has addressed this vulnerability in Cisco Webex Services, which are cloud based.
To avoid service interruption, customers who are using trust anchors with their SSO integration should upload a new identity provider (IdP) SAML certificate to Control Hub. For more information, see Manage single sign-on integration in Control Hub ["https://help.webex.com/en-us/article/nstvmyo/Manage-single-sign-on-integration-in-Control-Hub#Cisco_Task_in_List_GUI.dita_07fbdc21-41a0-482f-99dc-b8c17adbd087"].
Customers who need additional information are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Vulnerability Policy: To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy ["http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
Exploitation and Public Announcements: 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.
Source: This vulnerability was found during internal security testing.
Legal Disclaimer: SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads ["https://www.cisco.com/c/en/us/support/index.html"] page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC) ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"]. Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
When considering software upgrades ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"], customers are advised to regularly consult the advisories ["https://www.cisco.com/go/psirt"] for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"] or their contracted maintenance providers.
LEGAL DISCLAIMER DETAILS
CISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
Copies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories ["https://www.cisco.com/go/psirt"] page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"] for more information.
9.8 (Critical)
Vendor Fix
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
References
Acknowledgments
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"text": "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.\r\n\r\nCisco has addressed this vulnerability in the Cisco Webex service. However, customer action is necessary for affected organizations that are using trust anchors with their SSO integration.\r\n\r\nThere are no workarounds that address this vulnerability.\r\n\r\nTo avoid service interruption, customers who are using trust anchors with their SSO integration should upload a new identity provider (IdP) SAML certificate to Control Hub. For more information, see Manage single sign-on integration in Control Hub [\"https://help.webex.com/en-us/article/nstvmyo/Manage-single-sign-on-integration-in-Control-Hub#Cisco_Task_in_List_GUI.dita_07fbdc21-41a0-482f-99dc-b8c17adbd087\"].\r\n\r\n",
"title": "Summary"
},
{
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"text": "This vulnerability affected Cisco Webex Services, which are cloud-based, when they were configured to use trust anchors within the SSO integration with Control Hub.\r\n\r\nDetermine Whether Trust Anchors Are in Use\r\n\r\nOnly customers who use trust anchors were affected by this vulnerability. To determine whether trust anchors are in use, log in to the Webex Control Hub and verify the SSO configuration.",
"title": "Vulnerable Products"
},
{
"category": "general",
"text": "Only products listed in the Vulnerable Products [\"#vp\"] section of this advisory are known to have been affected by this vulnerability.",
"title": "Products Confirmed Not Vulnerable"
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{
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"text": "There are no workarounds that address this vulnerability.",
"title": "Workarounds"
},
{
"category": "general",
"text": "Cisco has addressed this vulnerability in Cisco Webex Services, which are cloud based.\r\n\r\nTo avoid service interruption, customers who are using trust anchors with their SSO integration should upload a new identity provider (IdP) SAML certificate to Control Hub. For more information, see Manage single sign-on integration in Control Hub [\"https://help.webex.com/en-us/article/nstvmyo/Manage-single-sign-on-integration-in-Control-Hub#Cisco_Task_in_List_GUI.dita_07fbdc21-41a0-482f-99dc-b8c17adbd087\"].\r\n\r\nCustomers who need additional information are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.",
"title": "Fixed Software"
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"title": "Vulnerability Policy"
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"text": "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.",
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"text": "This vulnerability was found during internal security testing.",
"title": "Source"
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"category": "legal_disclaimer",
"text": "SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT\r\n\r\nThe Cisco Support and Downloads [\"https://www.cisco.com/c/en/us/support/index.html\"] page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.\r\n\r\nCustomers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC) [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"]. Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.\r\n\r\nWhen considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories [\"https://www.cisco.com/go/psirt\"] for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"] or their contracted maintenance providers.\r\nLEGAL DISCLAIMER DETAILS\r\n\r\nCISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.\r\n\r\nCopies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories [\"https://www.cisco.com/go/psirt\"] page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"] for more information.",
"title": "Legal Disclaimer"
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"namespace": "https://wwww.cisco.com"
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"references": [
{
"category": "self",
"summary": "Cisco Webex Services Certificate Validation Vulnerability",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-cui-cert-8jSZYhWL"
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{
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{
"category": "external",
"summary": "Manage single sign-on integration in Control Hub",
"url": "https://help.webex.com/en-us/article/nstvmyo/Manage-single-sign-on-integration-in-Control-Hub#Cisco_Task_in_List_GUI.dita_07fbdc21-41a0-482f-99dc-b8c17adbd087"
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"url": "https://www.cisco.com/c/en/us/support/index.html"
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"url": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"
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"summary": "considering software upgrades",
"url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
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{
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"url": "https://www.cisco.com/go/psirt"
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],
"title": "Cisco Webex Services Certificate Validation Vulnerability",
"tracking": {
"current_release_date": "2026-04-16T18:52:15+00:00",
"generator": {
"date": "2026-04-16T18:52:18+00:00",
"engine": {
"name": "TVCE"
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"id": "cisco-sa-webex-cui-cert-8jSZYhWL",
"initial_release_date": "2026-04-15T16:00:00+00:00",
"revision_history": [
{
"date": "2026-04-15T15:52:49+00:00",
"number": "1.0.0",
"summary": "Initial public release."
},
{
"date": "2026-04-16T18:52:15+00:00",
"number": "1.1.0",
"summary": "Added information about trust anchor usage."
}
],
"status": "final",
"version": "1.1.0"
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"product_tree": {
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{
"branches": [
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"category": "product_family",
"name": "Cisco Webex Meetings",
"product": {
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"product_id": "CSAFPID-228295"
}
}
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"name": "Cisco"
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"vulnerabilities": [
{
"cve": "CVE-2026-20184",
"ids": [
{
"system_name": "Cisco Bug ID",
"text": "CSCwt37111"
}
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"notes": [
{
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"text": "Complete.",
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"product_ids": [
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"url": "https://software.cisco.com"
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"scores": [
{
"cvss_v3": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"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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"products": [
"CSAFPID-228295"
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}
],
"title": "Cisco Webex Meetings Certificate Validation Vulnerability"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
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.
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