Brief Summary: CVE-2026-10840 OpenShift Pipelines RBAC Misconfiguration Grants Any Authenticated User Cluster Wide Write Access

Introduction

The OpenShift Pipelines Operator ships an RBAC misconfiguration that silently grants every authenticated cluster user write access to Kueue scheduling resources and cert-manager certificate objects. On any affected OpenShift cluster, that access allows cross-tenant workload disruption and TLS certificate hijacking. The vulnerability has a CVSS score of 9.6 and had no patch at the time of disclosure. It affects every OpenShift Pipelines deployment, whether or not the Tekton Scheduler feature is enabled.

Red Hat OpenShift Pipelines is a cloud-native CI/CD solution based on Kubernetes and the Tektoncd project. The underlying tektoncd/operator manages TektonCD Pipelines, Dashboard, Triggers, and related components. As of 2026, 6,633 verified companies use Red Hat OpenShift, and the container management market exceeds $2.5 billion annually, so the blast radius of this vulnerability across enterprise environments is significant.

Technical Information

Root Cause: Overly Permissive ClusterRoleBinding

CVE-2026-10840 is classified under CWE-732 (Incorrect Permission Assignment for Critical Resource). MITRE defines this weakness as occurring when "the product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors." CWE-732 maps to two attack patterns that describe what happens here: CAPEC-1 (Accessing Functionality Not Properly Constrained by ACLs) and CAPEC-122 (Privilege Abuse).

The OpenShift Pipelines Operator ships a ClusterRoleBinding named tekton-scheduler-rolebinding that binds ClusterRole/tekton-scheduler-role to the system:authenticated group. In Kubernetes and OpenShift, the system:authenticated group includes every user, service account, and application pod that has successfully authenticated to the API server. So any developer, CI/CD pipeline, or compromised pod with valid credentials inherits these cluster-wide permissions:

According to the Bugzilla report, the RBAC objects are installed unconditionally, even when the Tekton Scheduler feature is disabled. Organizations that deployed the OpenShift Pipelines Operator but never enabled the Tekton Scheduler feature are still fully exposed.

Attack Vector 1: Kueue Workload Scheduling Disruption

When Kueue CRDs are present on the cluster (for example, installed via Red Hat OpenShift AI), any authenticated user can use the granted permissions to disrupt workload scheduling across tenants. Specifically, an attacker can:

1. Delete ResourceFlavor objects. ResourceFlavors define the resource quotas available to tenants, so removing them causes scheduled workloads to fail or become unschedulable.
2. Delete other tenants' Workload objects, which removes queued or running batch jobs that belong to other users or teams.
3. Change WorkloadPriorityClass objects to favor the attacker's own workloads or deprioritize everyone else's.

Standard kubectl commands are enough. The attacker needs no elevated privileges, social engineering, or specialized tooling. The attack undermines the core multi-tenancy isolation that Kueue provides for batch scheduling in shared clusters.

Attack Vector 2: cert-manager Confused Deputy Attack

When cert-manager is installed on the cluster, any authenticated user can create Certificate objects that target arbitrary Secrets. The Bugzilla report describes an attacker targeting the default ingress controller's TLS Secret (openshift-ingress/router-certs-default) so that cert-manager overwrites it with an attacker-influenced certificate.

This is a textbook confused deputy attack. The attacker cannot write Secrets directly, so they use cert-manager's ServiceAccount to write them instead, crossing authorization boundaries along the way. The consequences include:

1. TLS certificate hijacking. An attacker who overwrites the cluster's default ingress TLS certificate with one they control can intercept HTTPS traffic to any route on the cluster.
2. Manipulation of the certificate issuance pipeline. Creating or modifying Issuer objects gives the attacker control over how certificates are issued.

The confused deputy pattern makes this attack particularly insidious, because standard RBAC auditing might not flag it right away. The attacker never writes to the targeted Secrets. They instruct cert-manager to do it for them.

Exploitation Prerequisites

The attack requires only authenticated access to the OpenShift API server, which is the baseline access every cluster user has. Standard kubectl commands against the Kubernetes API are enough to exploit it. The CVSS 9.6 critical rating reflects the network-based attack vector, low attack complexity, and high impact across confidentiality, integrity, and availability.

Why This Matters for Multi-Tenant Clusters

Organizations that run both Kueue and cert-manager alongside OpenShift Pipelines face compounded risk, because both attack vectors are available at the same time. Compared to other 2026 OpenShift Pipelines CVEs (CVE-2026-33211, CVE-2026-34986), CVE-2026-10840 has a cluster-wide blast radius rather than one confined to a single namespace or tenant. It can also compromise TLS infrastructure, not just CI/CD pipeline resources.

Affected Systems and Versions

The vulnerability affects every version and deployment of the OpenShift Pipelines Operator (tektoncd/operator) that ships the tekton-scheduler-rolebinding ClusterRoleBinding. Based on the available information:

• The vulnerability is present whether the Tekton Scheduler feature is enabled or disabled, because the RBAC objects are installed unconditionally.
• Clusters are exploitable when Kueue CRDs (e.g., installed via Red Hat OpenShift AI) or cert-manager are also present on the cluster.
• As of 2026-06-04, Red Hat lists no fixed packages. The Bugzilla entry shows no target milestone or fix version assigned, and the bug status remains NEW.
• The most recent OpenShift Pipelines security advisory, RHSA-2026:21932, addresses CVE-2026-33186, CVE-2026-33211, and CVE-2026-34986 but does not include CVE-2026-10840.

Recommended Workarounds

No official patch exists, so administrators should consider the following actions. They come from Kubernetes RBAC documentation and CWE-732 mitigation guidance, not from Red Hat's official advisory for this CVE.

1. If the Tekton Scheduler feature is not in use, delete the ClusterRoleBinding with kubectl delete clusterrolebinding tekton-scheduler-rolebinding. The Bugzilla report confirms this has no functional impact when the feature is disabled.
2. If the Tekton Scheduler feature is required, recreate the ClusterRoleBinding with a more restrictive subject, such as specific ServiceAccounts or a dedicated group, instead of system:authenticated.
3. Use kubectl auth can-i to verify that authenticated users cannot write to Kueue or cert-manager resources.
4. Track the Bugzilla entry and the Red Hat CVE page for the official patch.

Caveat: Deleting the ClusterRoleBinding may conflict with operator reconciliation loops, and the operator may try to recreate the binding. Test any manual RBAC changes in a non-production environment first.

Vendor Security History

The OpenShift Pipelines ecosystem has had several security issues in 2026, which indicates that this component stack is an area of active security research:

• CVE-2026-33211: A flaw in the Tekton Pipelines git resolver that allows tenant exploitation, addressed in RHSA-2026:21932.
• CVE-2026-40161: Affects Tekton Pipelines git resolver versions 1.0.0 to 1.10.0.
• CVE-2026-33186: Another OpenShift Pipelines vulnerability addressed in RHSA-2026:21932.

Red Hat has a dedicated Product Security team and runs a PSIRT that follows a structured vulnerability management lifecycle. It publishes security advisories (RHSAs) for OpenShift Pipelines regularly. Still, the pattern of RBAC and authorization-related vulnerabilities in the Tekton operator suggests that Red Hat and cluster administrators should both look more closely at this component's permission model.

References

• NVD Entry for CVE-2026-10840
• Red Hat CVE Page for CVE-2026-10840
• Bugzilla Bug 2484720: tekton-scheduler-rolebinding grants system:authenticated write access
• RHSA-2026:21932 Security Advisory (OpenShift Pipelines)
• CWE-732: Incorrect Permission Assignment for Critical Resource
• tektoncd/operator GitHub Repository
• Tekton Operator Documentation
• Kubernetes RBAC Authorization Documentation
• Red Hat Vulnerability Management and Lifecycle
• CVE-2026-33211 (Related OpenShift Pipelines CVE)
• CVE-2026-40161 (Related Tekton Pipelines CVE)
• CVE-2026-33186 (Related OpenShift Pipelines CVE)