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8.7

NGINX Ingress Controller allows attackers to inject configuration

CVE-2026-55723 · published 3 months ago
Summary

NGINX Ingress Controller's configuration generator has a vulnerability that allows authenticated attackers with permission to create or modify custom resource definitions or Ingress annotations to inject arbitrary configuration directives. This could potentially lead to attackers creating or deleting files, disabling services, or gaining unauthorized access. To mitigate this issue, ensure that only authorized users have permission to create or modify these resources.

Original advisory text
When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an injection vulnerability exists in the configuration generator of NGINX Ingress Control...
When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an injection vulnerability exists in the configuration generator of NGINX Ingress Controller. Multiple user-controllable fields are written into the generated NGINX configuration without sanitization. An authenticated attacker with permission to create or modify these CRDs or annotations may craft values that inject arbitrary NGINX configuration directives.

Impact:
An authenticated attacker granted write access to NGINX Ingress Controller CRDs or Ingress annotations through the Kubernetes API may be able to inject arbitrary NGINX configuration directives, create or delete files, or disable services. 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.
References
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker full control
Severity
8.7 High
Exploitation
<1% chance of attack within 30 days
Type
CWE-76Improper Neutralization of Equivalent Special Elements
Timeline
Published15 Jul 2026
Updated4 Nov 2026
First seen15 Jul 2026
Sources
CVE-2026-55723 · NVD
CVE-2026-55723 · OSV
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