it's just slang.

it is not an actual word that people use in conversation, but it is an abbreviation of vulnerability used as slang among certain circles.

been a "word" since forever mate, i even remember using it in the 90s. and it's alright, you might just be young or haven't forayed much into the deeper corners of the web where 'vulns' get discussed.

We updated the submission title from “37% of sites use a JavaScript library with a known vuln–reality is probably worse” to that of the article.

Yes, but it's somewhat informal and only used in writing (it sounds a bit weird if you say it out loud).