Executive brief
Kyverno is a policy engine that enforces security rules in Kubernetes clusters, including verifying that container images are signed and trusted before admission. In affected versions, a configuration meant to exempt a single specific image from verification mistakenly exempts all images on a resource, allowing unsigned or untrusted images to run in the cluster despite policies requiring signature verification.
Technical details
The ImageValidatingPolicy evaluator fails to read the spec.images and spec.allowedValues fields when processing PolicyException objects, causing the entire resource to bypass image signature verification whenever exception match conditions are satisfied, rather than partially exempting only the listed images. An attacker with ability to create or modify PolicyException resources can craft exceptions that fully disable image verification controls for targeted workloads, allowing deployment of unsigned or malicious container images.
Affected products
- Kyverno Kyverno 1.14.0 through 1.19.0
Timeline
- 2026-09-26: disclosed: CVE-2026-100704 published
- 2026-09-10: patched: Fix released in version 1.19.1