Actually, the thing is to bypass $V=L$. So, is there a way to prove that (if consistent) $\mathsf{ZFC}$ can't prove that there exists a weakly inaccessible without first showing that $\mathsf{GCH}$ is relatively consistent? Obviously, if we can show that $\mathsf{ZFC}$ doesn't prove the consistency of a weakly inaccessible is much better.
The only really similar question I found is this, and I wasn't much too thorough in my web search because I'm pretty sure that this is just a curiosity.
PS. Answers using Easton magic are not allowed!