Before revision:  To prove our results, we demonstrate how financial networks with debt and CDSscan encode Boolean and arithmetic operations. Our results have practical importance for network stress tests and they reveal computational complexity as a new concern regarding the stability of the financial system .
After revision:  If naked CDSs are not present, we receive a simple polynomial-time algorithm. Our results are of practical importance for network stress tests and they reveal computational complexity as a new concern regarding the stability of the financial system .