A security issue was identified in ingress-nginx where the nginx.ingress.kubernetes.io/configuration-snippet annotation on an Ingress object (in the `networking.k8s.io` or `extensions` API group) can be used to inject arbitrary commands, and obtain the credentials of the ingress-nginx controller. In the default configuration, that credential has access to all secrets in the cluster.
This issue has been rated High (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L), and assigned CVE-2023-5043.
This bug affects ingress-nginx. If you do not have ingress-nginx installed on your cluster, you are not affected. You can check this by running `kubectl get po -n ingress-nginx`.
If you are running the “chrooted” ingress-nginx controller introduced in v1.2.0 (gcr.io/k8s-staging-ingress-nginx/controller-chroot), command execution is possible but credential extraction is not, so the High severity does not apply.
Multi-tenant environments where non-admin users have permissions to create Ingress objects are most affected by this issue.
Ingress Administrators should set the --enable-annotation-validation flag to enforce restrictions on the contents of ingress-nginx annotation fields.
If you find evidence that this vulnerability has been exploited, please contact secu...@kubernetes.io
See ingress-nginx Issue #10571 for more details.
This vulnerability was reported by suanve
CJ Cullen on behalf of the Kubernetes Security Response Committee