Kyverno from 1.16.0 before 1.19.2 fails to validate path segments in the resource argument of resource.get() and resource.post(), allowing namespaced CEL policies to escape their namespace. Tenants who can create a NamespacedValidatingPolicy can insert .. segments to read and write arbitrary cluster objects using the admission controller's ServiceAccount, leading to cluster takeover.
Kyverno from 1.19.1 before 1.19.2 contains a namespace isolation bypass in APICall Fetch() in pkg/engine/apicall/apiCall.go because path.Clean treats '?' as a path character, letting the namespace regex match segments inside the query string. Users who can create namespaced policies can supply a URLPath like /api/v1/nodes?x=/namespaces/default/ that passes validation while client-go requests the cluster-scoped endpoint, reading resources outside their namespace.
Kyverno from 1.17.0 before 1.19.2 contains a privilege escalation vulnerability that allows namespace-scoped tenants to modify resources in other namespaces through NamespacedMutatingPolicy targetMatchConstraints.expression CEL output lacking namespace checks. Attackers can emit a literal target such as another tenant's RoleBinding, which the cluster-wide background controller then mutates to add attacker subjects or alter Roles, NetworkPolicies, and ConfigMaps.
Kyverno before 1.19.2 contains a privilege escalation vulnerability that allows namespace admins to create resources beyond their RBAC because generate-rule admission checks verify the controller's permissions, not the author's. Attackers can create a namespaced Policy with generate rules targeting other namespaces or cluster-scoped kinds, making the background controller create or clone resources cluster-wide.
Kyverno before 1.19.2 contains a denial of service vulnerability that allows namespaced policy authors to exhaust admission controller CPU by submitting pathological wildcard patterns. Attackers can create a Policy with crafted match and exclude names evaluated by ValidateMatchExcludeConflict, pinning cores and causing cluster-wide webhook timeouts that block resource operations.
Kyverno before 1.19.2 contains a policy bypass vulnerability in the admissionpolicygenerator controller, which folds PolicyExceptions into generated ValidatingAdmissionPolicies while ignoring the --enablePolicyException, --exceptionNamespace, and policy kind gates. Users with namespaced create rights on PolicyExceptions can inject negated matchConditions into the generated policies to admit violating resources, bypassing cluster-wide enforcement.