The XZ Utils backdoor, discovered last week, and the Heartbleed security vulnerability ten years ago, share the same ultimate root cause. Both of them, and in fact all critical infrastructure open source projects, should be fixed with the same solution: ensure baseline funding for proper open source maintenance.\n
They sat on external blue for 5 year before it was stolen and they disclosed the vulnerability to Microsoft.
https://en.wikipedia.org/wiki/EternalBlue
I don’t see why we wouldn’t assume there is always something similar in their armoury.