If you examine the page https://www.isc2.org/Training/Self-Study-Resources then it shows the ISSAP and ISSMP concentrations having an official CBK book, but not the ISSEP. Perhaps this is one to send to ISC2 directly and ask if there's an up to date CBK.
I am preparing ISSEP too.
I don't think there is a "current" version and there is not a single CBK to cover all domain in ISSEP.
you might look at this post
I would say basically you can look at the
NIST 800-160 for enginerering related
where risk related: 800-30 conductingfor risk assessment and 800-37 for RMF
Thank you @csjohnng. I will definitely focus my attention on the NIST and additional resources which seem to have been updated this week by the way.
I saw the thread that you pointed to in your response and what was confusing was the post by @ToniHahn
on 7-11-2018 where she list references by domain. I was assuming that this was based on the domains before the recent changes.
I'm also thinking of paying the $2.5k for the ISC(2) official course.
In any event, I just hope ISC(2) addresses this lack of guidance for this exam. Paying $2.5K for the official course and another $600 for the exam is quite expensive and there not even is an updated CBK.