Database/Container, Kubernetes & orchestration

Kyverno: overlapping PolicyExceptions let a tenant bypass an enforce-mode policy

CVE-2026-84200Container, Kubernetes & orchestrationcurated

Impact

On a GPU cluster Kyverno is usually the thing standing between a tenant pod and the host: the policies that block hostPath mounts, privileged containers and direct device mounts are enforced here. When a policy in enforce mode is covered by two PolicyExceptions, the less restrictive one wins, so a tenant who names a resource to match the second exception's pattern (the advisory's example is a name containing 'ingress') gets admitted despite the policy. The practical result is a pod that mounts hostPath on a GPU node, which is a short step from the host filesystem, the container runtime socket and every other tenant's workload on that node. The bypass leaves normal-looking admission logs, so it does not announce itself.

Who can reach it

Any authenticated user who can create workloads in a namespace covered by a policy that has two or more PolicyExceptions attached; no cluster-admin rights needed, only the ability to choose the resource name.

What to do

Upgrade Kyverno to v1.13.0 or later (v1.9.0 through v1.12.7 are affected) and roll the admission controller deployment; no node drain or reboot is involved. Before and after the upgrade, audit existing PolicyExceptions for overlapping name patterns on the same policy - the more exceptions a policy carries, the wider the pre-upgrade exposure.

References

https://nvd.nist.gov/vuln/detail/CVE-2026-84200 https://github.com/kyverno/kyverno/security/advisories/GHSA-gg4x-fgg2-h9w9 https://www.vulncheck.com/advisories/kyverno-before-1.13.0-policy-bypass-via-multiple-exceptions

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.