---
title: "CVE-2026-91184: NGINX Gateway Fabric - Command Injection"
description: "NGINX Gateway Fabric contains a command injection caused by unescaped rendering of spec.basic.realm and spec.jwt.realm fields in AuthenticationFilter CRD, letting authenticated attackers inject arbitrary NGINX directives, exploit requires authenticated access to configure AuthenticationFilter."
url: https://panop.io/threat-heartbeat/CVE-2026-91184/
---

# CVE-2026-91184 NGINX Gateway Fabric - Command Injection

NGINX Gateway Fabric contains a command injection caused by unescaped rendering of spec.basic.realm and spec.jwt.realm fields in AuthenticationFilter CRD, letting authenticated attackers inject arbitrary NGINX directives, exploit requires authenticated access to configure AuthenticationFilter.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91184)

## Details

Type

Command Injection

Impact

Information Disclosure, Server Side Request Forgery, Broken Access Control

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Published

14 October 2026

Updated

15 October 2026

Weakness

[CWE-76](https://cwe.mitre.org/data/definitions/76.html)

## Vendor fix

Update to the latest version with fixed AuthenticationFilter rendering to properly escape realm fields.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91184](https://nvd.nist.gov/vuln/detail/CVE-2026-91184)
- [https://my.f5.com/manage/s/article/K000162609](https://my.f5.com/manage/s/article/K000162609)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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