Ingress-nginx `path` sanitization can be bypassed with newline character

CVE-2021-25748

Summary

A security vulnerability has been identified in ingress-nginx that allows an authenticated user to exploit newline characters in the spec.rules[].http.paths[].path field of an Ingress object. This manipulation can circumvent existing sanitization measures, enabling the unauthorized retrieval of the ingress-nginx controller's credentials, which by default possess access to all secrets within the Kubernetes cluster. This flaw poses a significant risk as it could lead to unauthorized access to sensitive information and requires immediate attention to mitigate potential exploitation.

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