External risk intelligence

Kyverno Authorization Bypass via Cleanup Policy Context Loader

CVE advisorySeverity: CRITICAL (CVSS 9.4)

CVE-2026-122304

Kyverno is a Kubernetes policy engine that operates internally within a cluster. Exploiting this vulnerability requires authenticated access to the cluster as a namespace admin to create or modify policies. While reachable over the network in some environments, it is not a public-facing internet service, and deployment occurs deep within internal infrastructure behind cluster controls.

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in Kyverno could allow administrators with limited permissions to gain broader access within a Kubernetes cluster. This bypasses intended security controls, potentially exposing sensitive information and allowing unauthorized modifications to critical cluster configurations. The primary concern is to verify if this specific technology is in use and, if so, to assess the potential exposure.

Admins could bypass restrictions.
Limits unauthorized access to data and configurations.
Confirm relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker with administrative access within a specific namespace could exploit this vulnerability by creating or modifying a CleanupPolicy. This policy would leverage context entries to read sensitive information from Secrets across different namespaces and alter critical webhook configurations, effectively bypassing intended security boundaries.

Namespace admin credentials required.
Malicious CleanupPolicy triggers vulnerability.
Allows reading secrets and modifying webhooks.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow a namespace administrator to bypass security restrictions, enabling them to read sensitive cross-namespace data and modify critical system configurations. This is possible when the cleanup controller is built with a nil policy, allowing crafted `CleanupPolicy` resources to access or alter data beyond their intended scope.

Cross-namespace Secrets and configurations.
Admin creates a malicious `CleanupPolicy`.
Unauthorized data access and modification.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Kyverno authorization bypass vulnerability requires immediate attention from teams managing Kubernetes and application deployments. Infrastructure or Platform Engineering teams are likely responsible for the core Kyverno installation, while Application Owners must be identified to understand the blast radius and business criticality of affected workloads. The initial step involves cataloging all Kyverno deployments, confirming external reachability, and assessing the impact on sensitive data and configurations within the cluster.

Platform and application owners should triage.
Verify Kyverno deployment reachability and scope.
Plan remediation and vendor coordination.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Kyverno?

Kyverno is a policy engine designed for Kubernetes. It functions as an admission controller, enabling teams to manage, validate, and mutate cluster configurations using Kubernetes-native policies. It helps ensure that resources deployed to a cluster comply with defined security and operational standards.

What is the authorization bypass in CVE-2026-122304?

This vulnerability, classified as CWE-863 (Incorrect Authorization), occurs because the Kyverno cleanup controller fails to properly scope its operations. By using a 'nil' policy during context loading, the system inadvertently grants elevated privileges to processes that should be restricted, allowing unauthorized access to resources.

How does an attacker trigger this vulnerability?

An attacker must already have permissions to manage resources within a specific namespace. They trigger the issue by creating a crafted 'CleanupPolicy' that includes specific 'apiCall' or 'globalReference' context entries. Standard, non-malicious use of cleanup policies or environments where namespace admins cannot create such policies do not trigger this bug.

How relevant is this CVE for my infrastructure?

According to Halo Surface Signal, this vulnerability is considered 'Unlikely' to be exploited from the public internet. Because Kyverno operates internally within your cluster, an attacker requires pre-existing, authenticated access as a namespace administrator. It is generally protected by your existing cluster-level security controls.

What should I do if I am running affected versions of Kyverno?

Begin by identifying all Kyverno instances in your environment to determine if they fall within the 1.17.0 to 1.19.2 range. Coordinate with your platform engineering team to assess which workloads rely on these versions and prioritize patching or updating the software to the secure version provided by the project maintainers.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.