Description: When NGINX Plus is configured as the data plane for NGINX Gateway Fabric, an injection vulnerability exists in the NGINX configuration generator component of NGINX Gateway Fabric. User-supplied string values from the Authentication Filter Custom Resource Definition clientID or cookieName fields, or in the clientSecret field of a Secret referenced by an Authentication Filter, are rendered directly into NGINX configuration templates without sanitization or escaping.

Impact: An authenticated attacker with permission to create or modify these resources may craft values that inject arbitrary NGINX configuration directives. This is a control plane issue; there is no data plane exposure.