I agree that it would be a good idea to define it explicitly when writing for a broader audience, but I don't think it's particularly egregious that they didn't. It's certainly something I could see myself forgetting.
Then again, the whole writeup appears to be AI-generated, so...
https://www.acronymfinder.com/Information-Technology/MCU.htm...
https://www.acronymfinder.com/LVAD.html
https://www.acronymfinder.com/Information-Technology/LPE.htm...
So what's missing is that keeping up-to-date with CVEs is important and some CVEs are Internet-nerd famous. Remember Heartbleed? Even some casual gamers I know had heard of it. And everyone who's mildly serious about sysadmin knows you want to defensively keep systems patched against important CVEs. The second layer of that, what the exploits actually are or do, is a second-layer term of art, one that one might miss the jargon for even if one has familiarity with the concepts.
To me, the fact that the page is obviously AI-assisted is way more upsetting than some guy not knowing what an acronym means. There's something about AI prose that is just so fucking tedious. It makes the mind glaze over.
I obviously do not expect someone who has merely heard of various CVEs before to know anything about the contents of those CVEs. The other poster said they had "read many CVEs", which I took to mean they have read many CVE disclosures, where the term is extremely common. Perhaps they meant that they've read about CVEs, in which case I can see why the term would not be on their radar.
Back in the day those of us breaking into shitty php sites didn't use LPE, we used "privesc", IIRC.
If you type "LPE" into English Wikipedia's search bar, and press "Enter", you'll be sent to a disambiguation page which contains a link to the relevant article.