CVE-2026-55723Network attack vector

Control-plane compromise via unsanitized configuration fields

Published Jul 15, 2026 · Updated Jul 15, 2026

Configuration injection in F5 NGINX Ingress Controller 5.0.0 through 5.5.1 allows remote authenticated users to inject NGINX directives. In 2026-lts-r1 through 2026-lts-r2, the configuration generator likewise writes user-controlled CRD and Ingress annotation fields into generated NGINX configuration without sanitization. Kubernetes API permission to modify those objects is required; successful injection can create or delete files or disable services, but F5 reports no data-plane exposure.

CVSS severity8.7
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Configuration injection in F5 NGINX Ingress Controller 5.0.0 through 5.5.1 allows remote authenticated users to inject NGINX directives. In 2026-lts-r1 through 2026-lts-r2, the configuration generator likewise writes user-controlled CRD and Ingress annotation fields into generated NGINX configuration without sanitization. Kubernetes API permission to modify those objects is required; successful injection can create or delete files or disable services, but F5 reports no data-plane exposure.

The record

CVE
CVE-2026-55723
Published
Jul 15, 2026
Updated
Jul 15, 2026
Vendor
F5 Networks
Product
NGINX Ingress Controller
Classifications
CWE-76
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2026-lts-r1 <2026-lts-r3
  2. Affected versionversion=5.0.0 <5.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

F5 Networks · NGINX Ingress Controllerversion=2026-lts-r1 <2026-lts-r3; version=5.0.0 <5.5.2

Published CVSS scores

8.3F5 NetworksCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
8.7F5 NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-76Improper Neutralization of Equivalent Special Elements

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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