Technical impact
Kyverno prior to 1.19.1 contains a namespace isolation bypass that allows a tenant to read resources in other namespaces by using percent‑encoded dot segments in the apiCall context entry of a Policy resource. The vulnerability arises from an inconsistency between the path validation performed during admission and the path used at execution time, which causes the namespace check to be ignored. The result is a confidentiality breach where an unauthorized tenant can access data that should be confined to other namespaces.
Affected Systems
All Kyverno deployments using version 1.19.0 or earlier, regardless of Kubernetes cluster size or configuration, are vulnerable. Any environment where Policies are created by low‑privilege ServiceAccounts can be impacted.
Risk and Exploitability
The CVSS score of 8.3 indicates a high severity. Attackers do not need elevated privileges; they only require the ability to create or modify Policy resources and the use of a ServiceAccount that controls the admission controller. The percentage‑encoded dot segments in the urlPath are interpreted differently during validation versus execution, enabling the bypass. No public exploits are documented and the EPSS score is not available, but the nature of the flaw suggests a moderate chance of exploitation in active environments. The vulnerability is not listed in the CISA KEV catalogue, indicating that no confirmed or widespread exploitation has been reported.
