シャブ is common slang for crystal methamphetamine.
Regular newspapers usually use the more politically-correct 覚醒剤【かくせいざい】, which literally means "stimulant drug", but nearly always refer to methamphetamine or cocaine. This being a tabloid (and perhaps because the term is a little more specific), they went with the stronger word シャブ, but out of that typical faux-coyness about "loaded" terms in Japanese media (*), opted to censor it.
As for the wider context, it's a bit off-topic, but:
Famous 80s artist ASKA was recently arrested for possession and use of said stimulants. The
恋人 愛人 part probably refers to the "friend"/"girlfriend" (didn't follow the details too closely) that was charged alongside him (and whose house would have apparently been used to store and consume the narcotics).
*: Apparently, it's really bad if kids get to see a slang term for drug spelt out on a subway ad, but totally fine if they get their fill of half-naked, boob-cupping, barely-legal models on the same ad.