CVE-2026-96615 in NGINX Gateway Fabric
Summary
by MITRE • 10/15/2026
Description NGINX Gateway Fabric has a vulnerability when it is configured with Gateway
Custom Resource Definition (CRD) and have an authenticated gRPC connection with NGINX Agent. A namespaced
authenticated attacker with access to a service account may impersonate the authenticated NGINX Agent gRPC connection to read TLS private keys of Gateway deployments in another namespace.
Impact A remote authenticated attacker may be able to read TLS private keys of Gateway deployments in another namespace.
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.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified within NGINX Gateway Fabric represents a critical security flaw rooted in the improper handling of identity verification and authorization boundaries between distinct namespaces within a Kubernetes environment. This issue specifically affects configurations where the system utilizes Gateway Custom Resource Definitions alongside an authenticated gRPC connection to the NGINX Agent. The core technical failure lies in the ability of a namespaced, authenticated attacker who possesses access to a specific service account to impersonate the legitimate authentication context of the NGINX Agent's gRPC channel. By exploiting this identity confusion or insufficient validation mechanism, the malicious actor can trick the control plane into treating their requests as if they originated from the trusted NGINX Agent process itself. This misdirection allows the attacker to bypass standard namespace isolation policies that would otherwise restrict access to sensitive configuration data residing in other namespaces.
From a technical perspective, this flaw constitutes an authorization failure where the system fails to strictly bind the authenticated identity of the gRPC connection to the specific privileges intended for the NGINX Agent role across different resource boundaries. The attacker leverages their existing permissions within one namespace to forge or replay credentials that are accepted by the control plane as valid agent authentication tokens. Once this impersonation is successful, the system grants access to internal secrets management functions, specifically allowing the retrieval of TLS private keys associated with Gateway deployments located in separate namespaces. This indicates a breakdown in the principle of least privilege and proper scope validation for service-to-service communication within the cluster's control plane architecture.
The operational impact of this vulnerability is severe due to the sensitivity of the exposed data. The ability to read TLS private keys from gateway deployments across multiple namespaces effectively compromises the confidentiality and integrity of encrypted communications managed by those gateways. An attacker possessing these private keys can perform man-in-the-middle attacks, decrypting traffic intended for legitimate users or impersonating the services protected by those certificates. This undermines trust in the entire service mesh infrastructure. It is crucial to note that this vulnerability is strictly a control plane issue; there is no direct exposure of data on the data plane itself. The risk is confined to administrative and configuration access, meaning exploitation requires prior authenticated access within the cluster rather than remote network-level attacks against public endpoints.
In terms of industry standard classifications, this vulnerability aligns with CWE-269 Improper Privilege Management, as it involves an actor obtaining privileges beyond their intended scope through identity impersonation. Furthermore, it relates to CWE-732 Incorrect Permission Assignment for Critical Resource, given that sensitive cryptographic materials are accessible by unauthorized entities due to flawed access control logic. From a tactical standpoint within the MITRE ATT&CK framework, this behavior corresponds to T1098 Account Manipulation, specifically through SSH Key Addition or API Credential Impersonation techniques used to maintain persistent access and escalate privileges within the Kubernetes environment. The exploitation path also reflects aspects of T1552 Unsecured Credentials, as it involves the theft of sensitive authentication material that facilitates further compromise.
Mitigation strategies must focus on tightening identity verification protocols and enforcing strict namespace isolation for control plane operations. Administrators should ensure that NGINX Gateway Fabric is updated to a patched version where this impersonation vector has been closed through enhanced validation of gRPC connection identities against their expected roles and namespaces. Additionally, implementing robust service account permissions using Kubernetes RBAC policies can limit the blast radius if an attacker gains initial access. It is advisable to audit all service accounts for excessive privileges and ensure that cross-namespace secret access is explicitly denied by default unless absolutely necessary for specific operational requirements. Regularly rotating TLS certificates and monitoring control plane logs for anomalous gRPC authentication patterns from unexpected sources will also help in detecting potential exploitation attempts before significant damage occurs.