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NGINX Gateway Fabric configuration directive injection via CRD fields

IdentifiersCVE-2026-11311CWE-74

CVE-2026-11311 is a high-severity injection vulnerability in the NGINX configuration generator component of NGINX Gateway Fabric when NGINX Plus is configured as the data plane. The flaw arises because user-controlled string values from the NginxProxy Custom Resource Definition (CRD) serverTokens field and the AuthenticationFilter CRD extraAuthArgs field are rendered directly into generated NGINX configuration templates without proper sanitization or escaping. An authenticated attacker with permission to create or modify these CRDs can supply crafted values that inject arbitrary NGINX configuration directives into the generated configuration. The issue is described as a control-plane vulnerability; the trigger is through management-plane configuration rather than direct data-plane request handling.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an authenticated attacker with CRD modification rights to alter the generated NGINX configuration by injecting arbitrary directives. Based on the provided content, this can lead to unauthorized proxy behavior, exposure of sensitive data from the NGINX pod filesystem, proxying or redirecting traffic to attacker-controlled endpoints, and denial of service if the injected configuration prevents NGINX from reloading or causes service instability. The primary security impact is compromise of configuration integrity with consequential confidentiality, integrity, and availability effects in Kubernetes environments using NGINX Gateway Fabric.

Mitigation

If you can’t patch tonight, do this now.

Until patches are applied, restrict permission to create or modify the affected Custom Resource Definitions to trusted administrators only, specifically the NginxProxy serverTokens field and the AuthenticationFilter extraAuthArgs field. Review RBAC assignments in the Kubernetes cluster to minimize who can alter these resources, and monitor generated NGINX configuration and reload failures for signs of abuse. If feasible, avoid exposing untrusted users to workflows that can influence these CRD fields.

Remediation

Patch, then assume compromise.

Upgrade NGINX Gateway Fabric to a fixed release. The provided content states affected versions include 2.3.0 through 2.6.3, with fixes in version 2.6.4. Remediation also requires correcting the configuration generator logic so that user-supplied values from the NginxProxy serverTokens field and AuthenticationFilter extraAuthArgs field are properly sanitized and escaped before being rendered into NGINX configuration templates. Software versions that have reached End of Technical Support were not evaluated.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
F5Nginx Gateway Fabricapplication
F5Nginx Plusapplication
NginxGateway Fabricapplication

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Threat actor evidence

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Detection signatures

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Vendor-by-vendor mapping

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Social activity1

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