A DoS issue in YAML parsing – CVE-2019-11253

XML bombs, or billion laughs attacks, are popular with any XML parsing code. Similar to parsing issues in XML, this was a parsing issue in YAML files that were sent to kube-apiserver. If a YAML file sent to the server has recursive references, it triggers the kube-apiserver to consume CPU resources, which causes availability issues on the API server. In most cases, requests parsed by kube-apiserver are restricted to authenticated users, so unauthenticated users should not be able to trigger this issue. There was an exception to this rule in the Kubernetes versions preceding 1.14 that allowed unauthenticated users to check whether they could perform an action using kubectl auth can-i.

This issue is similar to CVE-2019-1002100, but is more severe as unauthenticated users can also trigger this issue.

Mitigation strategy

You can use the following strategies to harden your cluster against this issue and issues similar to CVE...