Security and Vulnerabilities

I am a student in Cyber Security in Letterkenny Institute of Technology in Ireland and I am doing a case study about Graph Hopper.

1.Are some parts more susceptible to code vulnerabilities?
2.How does the system’s interaction with external systems put it at risk?
3.What are the trust boundaries of the system?
5.Was there ever any security risks?
6.How do you protect Confidentiality, Integrity and Availability of data? and how could it be compromised?
7.Can you tell me about one vulnerability bug? What was the security risk? and how did you fix it?
8.How many software developers worked on the vulnerability bug to fix it if known?
I would appreciate any advice about the aforementioned. Thank you.