CVE-2026-122312
Description
A flaw was found in Kyverno. An authenticated user with permissions to create namespaced policies can bypass namespace isolation restrictions by supplying a specially crafted API call URL path containing query strings. Because the path validation mechanism improperly handles query characters, cluster-scoped requests can appear to target an allowed namespace. This flaw allows an attacker to access and read resources outside their assigned namespace, leading to unauthorized information disclosure.
Statement
This vulnerability is rated as Important severity because authenticated tenants with permissions to manage namespaced policies can break isolation boundaries and retrieve cluster-scoped or cross-namespace resources. Although exploitation requires existing privileges to create policy resources, the flaw compromises the integrity of multi-tenant environments by allowing unauthorized read access via the controller's elevated API privileges. Red Hat OpenShift and other Red Hat offerings do not include or distribute Kyverno by default.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
--- CME Mitigation Guidance (2026-11-06) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to canonicalize APICall URL paths using standard URL parsing to isolate path components from query parameters before evaluating namespace restrictions: upgrade to Kyverno 1.19.2 (or the corresponding fixed Red Hat builds), which parse URL components using net/url via canonicalizeURLPath, evaluate namespace restrictions strictly against the URL path component, reject path traversal segments across policies, and restrict mutating policy targets to their respective namespaces, closing all 2 injection vectors (crafted APICall URLPath containing query parameters with decoy namespace segments, path traversal segments in policy resource paths). Until patched, this is a concern on Kubernetes clusters where authenticated users have permissions to create or manage namespaced Kyverno policies, so Restrict RBAC permissions for creating or updating namespaced Kyverno policies to trusted administrators to prevent unauthorized cross-namespace APICalls. As a compensating measure, Configure Kubernetes API server audit logging to detect cluster-scoped resource requests originating from Kyverno controller service accounts that contain unexpected query parameters. These controls limit blast radius and contain exploitation, but they do not fix the underlying parser differential defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-921 URL Request Path Canonicalization Before Authorization (high)
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
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