LastPass is reporting they’ve detected suspicious activity in their network. User passwords weren’t stolen but other information (account email addresses, password reminders, server per user salts, and authentication hashes) was. What this means is you should change your LastPass password immediately since this will update the salts and hashes.
You should have received a notice by now of this breach and to change your password, but even if you haven’t don’t wait. And if you haven’t already, enable multifactor authentication on your account. This will further protect you should someone else try to change your password.