CVE-2026-55723

HIGH CVSS 4.0: 8.7 EPSS 0.29%
Updated Jul 16, 2026
F5
Parameter Value
CVSS 8.7 (HIGH)
Affected Versions 3.6.0 — 5.5.2
Fixed In 5.5.2
Type CWE-76
Vendor F5
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
Low
Partial disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 3

Configuration From (including) Up to (excluding)
F5 Nginx_Ingress_Controller
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
3.6.0 <= 3.7.2
F5 Nginx_Ingress_Controller
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
4.0.0 <= 4.0.1
F5 Nginx_Ingress_Controller
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
5.0.0 5.5.2