Are we allowed mention black mold to future tenants? [MA]

We’re moving out early because black mold was found and is potentially causing me health issues. The landlord, who we’ve had lots of issues with, refused to fix the leak causing it and refused to treat the mold properly so we’ve been exposed without knowing for months. It’s covered by drywall but a hole cut to drain the water showed extensive molds They tried to say we couldn’t move out but when they found out we had photos and records of the mold they immediately said we could move out and have a month of rent back as long as we didn’t sue or report them. They’re still refusing to treat the mold but we’re moving out so whatever.

We just received notice that they’re showing our apartment while we’re both working from home. I’m considering informing the potential tenants about the mold issue, but I don’t want to get in any legal trouble. They made us sign a form promising we would never say anything disparaging about them in order to leave early. I’m not sure how enforceable that is and I feel bad letting someone move in without knowing about a serious health hazard.

TLDR: Our landlord is showing our apartment that has hidden black mold. Can we tell the prospective tenants?