GHSA-23VG-4CJM-66Q5 kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion

Summary openapi3filter.ValidationHandler.Middleware validates requests with kin-openapi's legacy router, which selects an OpenAPI operation from the decoded URL.Path. The method is documented as implementing gorilla/mux.MiddlewareFunc, but a downstream gorilla/mux router configured with...