# CVE-2026-76423: Cisco ISE REST API authentication bypass

Source: https://junglewise.ai/threats/cve-2026-76423-cisco-ise-rest-api-authentication-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-16. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-76423 · Severity: critical · CVSS 10 · Published 2026-09-16

Cisco Identity Services Engine (ISE) is an identity and access management platform that controls network access and device authentication for enterprises. A critical vulnerability in its REST API allows unauthenticated remote attackers to gain administrative access without credentials, enabling them to read and modify all ISE configuration and identity data. This could lead to network access policy manipulation, credential theft, and complete compromise of access controls.

Technologies: [Cisco Identity Services Engine](https://junglewise.ai/threats/technologies/identity-services-engine), [Cisco Identity Services Engine Passive Identity Connector](https://junglewise.ai/threats/technologies/identity-services-engine-passive-identity-connector). Vendors: [Cisco](https://junglewise.ai/threats/vendors/cisco).

## Quick answers

**Is CVE-2026-76423 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76423 being exploited in the wild.

**How severe is CVE-2026-76423?** Critical severity, with a CVSS score of 10, published 16 September 2026.

**Which products and versions are affected?** Cisco Identity Services Engine <UNKNOWN>; Cisco Identity Services Engine Passive Identity Connector <UNKNOWN>.

**Is there a fix for CVE-2026-76423?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-76423 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-76423?** Check whether you run Cisco Identity Services Engine or Cisco Identity Services Engine Passive Identity Connector at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

CVE-2026-76423 is an authentication bypass vulnerability in the Cisco ISE REST API resulting from insufficient authorization checks on the exposed web service. An attacker can send a crafted HTTP request to the REST API port without providing valid credentials to achieve administrative access. The vulnerability has a CVSS score of 10.0 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) indicating it requires no authentication, no user interaction, and affects multiple systems. A successful exploit grants full read and write access to ISE configuration and identity data. Cisco has released software patches; no workarounds are available.

## Affected products

- Cisco Identity Services Engine <UNKNOWN>
- Cisco Identity Services Engine Passive Identity Connector <UNKNOWN>

## Timeline

- 2026-09-16: disclosed: CVE-2026-76423 published

## References

- [https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-multi-hrP9jQSQ](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-multi-hrP9jQSQ)

## Related threats

- [Cisco Identity Services Engine authorization bypass in management interface](https://junglewise.ai/threats/cve-2026-20183-a-vulnerability-in-the-web-based-management-interface-of-cisco)
- [Cisco Identity Services Engine authorization bypass in certificate enrollment](https://junglewise.ai/threats/cve-2026-20241-a-vulnerability-in-the-authorization-mechanism-of-cisco-identity)
- [A vulnerability in an API of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to bypass authentication.](https://junglewise.ai/threats/cve-2026-76460-cisco-identity-services-engine-incorrect-privileged-api-use)
- [Cisco ISE SQL and HQL injection in APIs](https://junglewise.ai/threats/cve-2026-76451-cisco-ise-sql-and-hql-injection-in-apis)
- [Cisco Identity Services Engine SQL and HQL injection](https://junglewise.ai/threats/cve-2026-76450-cisco-identity-services-engine-sql-and-hql-injection)