Check out the ROCA attack:

www.techtarget.com/cybersecurity/tip/The-ROCA-vulnerability-How-it-works-and-what-to-do-about-it%3famp=1

In practice it was confined to specific TPM modules, but in principle it shows how one flaw in the RNG can jeopardize the whole system.

I also remember seeing a similar vuln in certificates where an attacker _generated_ millions of certs and was able to somehow get the private cert by trying every possible seed for the RNG. (Like seeding every second from 2003-2011 for example, then generating a cert with it). I know I'm getting major parts of this wrong but it conveys the general idea.