It seems that the JSON Schema parser is susceptible to stack overflow if given a sufficiently nested schema. We definitely can't allow the server to crash when parsing a schema, so recursion must be limited in some fashion.

Reproduction steps vary based on the hardware of the machine, but this schema was able to trigger it at least once on my workstation: https://gist.github.com/ksuarz/d5caa6fc8a9fb003e22cf92eb78596a4