Kyverno before 1.19.2 contains an unchecked type assertion in its variable-substitution engine that allows users who can submit resources to crash the policy engine. Attackers can submit resources with non-string fields referenced by {{- variable }} shallow substitution in policies, causing a panic that yields webhook denial of service and policy bypass under failurePolicy Ignore.

Kyverno before 1.19.2 contains an unchecked type assertion in its variable-substitution engine that allows users who can submit resources to crash the policy engine. Attackers can submit resources with non-string fields referenced by {{- variable }} shallow substitution in policies, causing a panic that yields webhook denial of service and policy bypass under failurePolicy Ignore.