The routesrv component exposes the full cluster route topology (Ingress/RouteGroup configurations, backend URLs, filter chains, OAuth/OIDC callback paths) and cache-cluster topology (Redis/Valkey shard addresses) over plain HTTP with zero authentication. Any pod in the Kubernetes cluster can reach routesrv via its predictable DNS name and retrieve sensitive cluster-wide routing and cache infrastructure data.
The Kubernetes admission webhook handler reads the entire request body using io.ReadAll(r.Body) without any size limit. Any client that can reach the webhook port within the cluster can send a multi-GB payload, causing the skipper process to exhaust memory and be OOM-killed. This disrupts all Kubernetes admission control, potentially blocking all pod creation and updates.
A wrong policy can be an open door. You have to check input.attributes.request.http.truncated_body in your policy.
zalando/skipper's OpenPolicyAgent integration silently bypasses request-body inspection on HTTP/1.1 Transfer-Encoding: chunked and HTTP/2 requests that omit the content-length pseudo-header. When the opaAuthorizeRequestWithBody filter is configured, the OpenPolicyAgentInstance.ExtractHttpBodyOptionally helper produces an empty raw_body for any request whose Content-Length header is missing, while the underlying chunked body still flows through to the upstream service. Rego policies that gate on input.parsed_body (e.g. "deny when a forbidden field is present") evaluate against an empty …
When running Skipper as an Ingress controller, users with permissions to create an Ingress and a Service of type ExternalName can create routes that enable them to use Skipper's network access to reach internal services.
Arbitrary code execution through lua filters. The default skipper configuration before v0.23 was -lua-sources=inline,file. The problem starts if untrusted users can create lua filters, because of -lua-sources=inline , for example through a Kubernetes Ingress resource. The configuration inline allows these user to create a script that is able to read the filesystem accessible to the skipper process and if the user has access to read the logs they an read …
Zalando Skipper v0.13.236 is vulnerable to Server-Side Request Forgery (SSRF).
In Zalando Skipper before 0.13.218, a query predicate could be bypassed via a prepared request.