CVE-2026-11311

Think of NGINX Gateway Fabric as a system that automatically builds NGINX “instructions” (config files) for you. This flaw means some user-provided text from configuration fields can be inserted into those instructions without being properly checked or cleaned. If someone who has access to change those configuration records is malicious, they could potentially add extra “directives” to the generated NGINX configuration.

This matters to you if you run or manage F5 NGINX Gateway Fabric, especially when NGINX Plus is configured as the data plane. Because this is a control plane issue, it depends on whether an attacker can create or modify the relevant Custom Resource Definitions—so it’s most relevant in environments where attackers could gain that level of access. If you don’t use NGINX Gateway Fabric (or you don’t use NGINX Plus as its data plane), you may not be affected.

This is rated AMBER because the issue is serious (it can lead to injection of arbitrary NGINX configuration), but there is no public exploit reported and no known exploitation in the wild per the provided information. It’s still “patch-now” style work because it was discovered as part of a new patch and relies on an attacker already having authenticated permission to alter configuration records. Act soon to reduce the chance of a misused or compromised control-plane account.

1. Check whether you use F5 NGINX Gateway Fabric with NGINX Plus as the data plane. 2) Ask your F5/NGINX administrator or IT vendor to apply the available patch for CVE-2026-11311 and confirm the fix is active. 3) Review who can create or modify the affected Custom Resource Definitions (especially the fields named serverTokens and extraAuthArgs) and tighten access if needed.