This vulnerability (CVE-2026-11311) affects F5's NGINX Gateway Fabric version 2.5.0, specifically in the NGINX configuration generator component when NGINX Plus is used as the data plane. It allows authenticated users with specific permissions to inject arbitrary NGINX configuration directives through unsanitized input fields in certain Custom Resource Definitions. The vulnerability is classified under CWE-76 (Improper Neutralization of Equivalent Special Elements). Although the injection can alter configuration, there is no direct exposure of the data plane from triggering this issue. No official remediation or patch has been released as of the publication date.

Successful exploitation can lead to injection of arbitrary NGINX configuration directives, potentially compromising the integrity and behavior of the NGINX Gateway Fabric deployment. The CVSS score of 8.1 indicates high severity with high confidentiality and integrity impact but no impact on availability. However, there is no direct data plane exposure, which may limit the attack surface. No known exploits are reported in the wild at this time.

No official patch or remediation guidance is currently available from the vendor. Users should monitor the vendor's advisories for updates. Until a fix is provided, restrict permissions to create or modify the affected Custom Resource Definitions to trusted administrators only to reduce the risk of exploitation.