CVE-2026-76423: Cisco ISE API Authentication Bypass Vulnerability

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 28 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.6%

EPSS score, percentile 47.8 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

10.0 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• 3.1.0
• 3.1.0 p1
• 3.1.0 p3
• 3.1.0 p2
• 3.2.0
• 3.1.0 p4

and 11 more in the table below

Versions by product

Source: CISA KEV 2026.10.28, as of 28 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unknown.

And 36 more version entries in the CVE record.

Versions not listed are: unknown.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

A vulnerability in the REST API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to gain administrative access to an affected device. This vulnerability is due to the REST API web service being exposed with insufficient authorization checks. An attacker could exploit this vulnerability by sending a crafted HTTP request to the exposed REST API port. A successful ex…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-76423 to its Known Exploited Vulnerabilities (KEV) catalog, as of 28 Oct 2026.
• The CVE record was published on 16 Sep 2026.
• The CVE record carries a CVSS v3.1 base score of 10.0 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.6% (percentile 47.8), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.

Source: CISA KEV 2026.10.28, as of 28 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

Cisco ISE API Authentication Bypass Vulnerability

A vulnerability in the REST API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to gain administrative access to an affected device. This vulnerability is due to the REST API web service being exposed with insufficient authorization checks. An attacker could exploit this vulnerability by sending a crafted HTTP request to the exposed REST API port. A successful exploit could allow the attacker to read and modify ISE configuration and identity data with administrative privileges.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline

Known exploited Cisco vulnerabilities

• CVE-2026-76519: Cisco Secure Email Gateway Relative Path Traversal Vulnerability (added 14 Oct 2026)
• CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability (added 30 Sep 2026)
• CVE-2026-76460: Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability (added 16 Sep 2026)
• CVE-2026-76461: Cisco Secure Email Gateway SQL Injection Vulnerability (added 14 Sep 2026)
• CVE-2026-20079: Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability (added 9 Sep 2026)