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CVE-2026-91184

8.8, high

Description NGINX Gateway Fabric has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced…

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
8.8, high high CVSS v3.1
EPSS, next 30 days
0.5% higher than 40.1% of scored CVEs
Exploitation
No public evidence
Published
14 Oct 20264 days ago

Description

Description NGINX Gateway Fabric has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic "<realm>";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway's data-plane config. Impact A remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric AuthenticationFilter CRD and may be able to read every co-located tenant's mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants' routes. There is no data plane exposure; this is a control plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Details

Vendor
F5
Product
NGINX Gateway Fabric
Weakness
CWE-76 (opens in a new tab)
Status
Awaiting analysis
Updated
14 Oct 2026
Assigner
f5sirt@f5.com

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

References 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other F5 CVEs

Every F5 CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-94127 F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability KEV EPSS 2% 9.8, critical
  • CVE-2025-53521 F5 BIG-IP Stack-Based Buffer Overflow Vulnerability KEV EPSS 2% 9.8, critical
  • CVE-2023-46747 F5 BIG-IP Configuration Utility Authentication Bypass Vulnerability KEV EPSS 97% 9.8, critical
  • CVE-2023-46748 F5 BIG-IP Configuration Utility SQL Injection Vulnerability KEV EPSS 4% 8.8, high
  • CVE-2022-1388 F5 BIG-IP Missing Authentication Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2021-22986 F5 BIG-IP and BIG-IQ Centralized Management iControl REST Remote Code Execution Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2021-22991 F5 BIG-IP Traffic Management Microkernel Buffer Overflow KEV EPSS 61% 9.8, critical
  • CVE-2020-5902 F5 BIG-IP Traffic Management User Interface (TMUI) Remote Code Execution Vulnerability KEV EPSS 100% 9.8, critical

Beyond this page

Is CVE-2026-91184 in your network?

This page tells you how dangerous CVE-2026-91184 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-91184 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 18 Oct 2026, not the live upstream state.