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

> Unauthenticated remote attackers can bypass authentication to gain administrative access and modify configuration or identity data in Cisco ISE.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** GHSA-877h-9m58-fr39

## What is CVE-2026-76423?

CVE-2026-76423 is a critical authentication bypass vulnerability in Cisco ISE Passive Identity Connector, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2026-76423?


## How do I fix CVE-2026-76423?

No fix has been published for CVE-2026-76423 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76423 being exploited?

There is no known exploitation of CVE-2026-76423 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76423 and fix it if it is affected.

What it is: CVE-2026-76423 is a critical authentication bypass vulnerability in Cisco ISE Passive Identity Connector, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76423 in the wild and no public exploit code.

Affected product: Cisco ISE Passive Identity Connector. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76423/ (Markdown: https://insights.sbomify.com/CVE-2026-76423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76423
- OSV: https://osv.dev/vulnerability/CVE-2026-76423

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-76423/
Summaries are generated and may contain mistakes; the official description above is the record.