Cisco Security Advisory
Cisco Identity Services Engine Authentication Bypass Vulnerabilities
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X
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Multiple vulnerabilities in Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC) could allow a remote attacker to access or manipulate data, obtain sensitive information, or cause a reload of certificate and key material on an affected device.
For more information about these vulnerabilities, see the Details section of this advisory.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-multiauth-bypass-sgD2HbL4This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of September 16, 2026, Security Advisories. In addition, for further documentation of improvements and fixes in Cisco Identity Services Engine, see Cisco Identity Services Engine Security Hardening Release: September 2026.
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Vulnerable Products
CVE-2026-76439: At the time of publication, this vulnerability affected Cisco ISE, regardless of device configuration.
CVE-2026-76444, CVE-2026-76446, and CVE-2026-76447: At the time of publication, these vulnerabilities affected Cisco ISE and Cisco ISE-PIC, regardless of device configuration.
For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
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The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit another vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerabilities.
Details about the vulnerabilities are as follows:
CVE-2026-76439: Cisco ISE Remote Code Execution Vulnerability
A vulnerability in the endpoint posture status reporting functionality of the guest portal web application of Cisco ISE could allow an unauthenticated, remote attacker to submit forged posture status events into the endpoint posture pipeline.
This vulnerability is due to insufficient authentication on an internal interface that is exposed through the guest portal. An attacker could exploit this vulnerability by sending a crafted request to an affected system. A successful exploit could allow the attacker to manipulate the posture status on the affected system.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu73771
CVE ID: CVE-2026-76439
Security Impact Rating (SIR): Medium
CVSS Base Score: 5.3
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCVE-2026-76444: Cisco ISE Information Disclosure Vulnerability
A vulnerability in an internal service of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to retrieve sensitive configuration information from an affected device.
This vulnerability is due to missing authentication on the Policy Runtime Repository Table (PRRT) service. An attacker could exploit this vulnerability by sending a crafted request to an affected device. A successful exploit could allow the attacker to obtain sensitive configuration information from the affected device.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu73786
CVE ID: CVE-2026-76444
Security Impact Rating (SIR): Medium
CVSS Base Score: 5.3
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NCVE-2026-76447: Cisco ISE Certificate Reload Vulnerability
A vulnerability in the Online Certificate Status Protocol (OCSP) responder of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to cause an administrative reload of the OCSP responder certificate and key material.
This vulnerability is due to missing authentication on a function of the OCSP responder. An attacker could exploit this vulnerability by sending a crafted request to an affected device. A successful exploit could allow the attacker to cause the OCSP responder to reload certificate and key material on demand.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu73832
CVE ID: CVE-2026-76447
Security Impact Rating (SIR): Medium
CVSS Base Score: 5.3
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LCVE-2026-76446: Cisco ISE External Entity Injection Vulnerability
A vulnerability in an API of Cisco ISE and Cisco ISE-PIC could allow an authenticated, remote attacker to read specific files on the underlying operating system of an affected device.
This vulnerability is due to improper restriction of XML external entity references. An attacker could exploit this vulnerability by sending a crafted request to an affected device. A successful exploit could allow the attacker to read specific files on the affected system that the underlying process has permission to access.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu73808
CVE ID: CVE-2026-76446
Security Impact Rating (SIR): Medium
CVSS Base Score: 4.9
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
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There are no workarounds that address these vulnerabilities.
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Cisco considers any workarounds and mitigations (if applicable) to be temporary solutions until an upgrade to a fixed software release is available. To remediate these vulnerabilities and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.
Fixed Releases
At the time of publication, the release information in the following table was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
The left column lists Cisco software releases, and the center and right columns indicate whether a release was affected by the vulnerabilities that are described in this advisory and which release included the fix for these vulnerabilities.
Cisco ISE or ISE-PIC Release First Fixed Release for CVE-2026-76439, CVE-2026-76446, and CVE-2026-76447 First Fixed Release for CVE-2026-76444 3.2 and earlier Migrate to a fixed release. Not vulnerable. 3.3 3.3 Patch 12 Not vulnerable. 3.4 3.4 Patch 7 3.4 Patch 7 3.51 3.5 Patch 4 3.5 Patch 4 1. Cisco ISE-PIC has reached the end-of-sale date. Release 3.4 is the last supported release.For instructions on upgrading a device, see the Upgrade Guides on the Cisco Identity Service Engine support page.
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
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The Cisco PSIRT is aware that a public announcement is available for the vulnerabilities that are described in this advisory.
The Cisco PSIRT is not aware of any malicious use of the vulnerabilities that are described in this advisory.
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Cisco would like to thank the following people for reporting these vulnerabilities:
- Li Jiantao and Tevel Sho of STAR Labs SG Pte. Ltd: CVE-2026-76439, CVE-2026-76444, CVE-2026-76446, CVE-2026-76447
- Nicholas Kloster, Independent Security Researcher: CVE-2026-76447
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
For additional information on Cisco's vulnerability management, disclosure cadence, and software patching strategy, see Cisco's Transition to a Risk-Based Vulnerability Disclosure Model.
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Show LessVersion Description Section Status Date 1.1 Added an additional researcher. Source Final 2026-SEP-24 1.0 Initial public release. - Final 2026-SEP-16
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SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads 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). 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, customers are advised to regularly consult the advisories 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) or their contracted maintenance providers.
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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 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 for more information.