Valve says the leak features phone numbers that previously received a one-time passcode, but they're not associated with a Steam account, password, or other personal data.

A leak of old text messages sent to Steam customers with one-time codes for logins was “not a breach of Steam systems,” Valve says in a post published Wednesday. Valve’s response follows news that a hacker is allegedly in possession of 89 million user records and put them up for sale for $5,

An apparent leak has exposed the phone numbers and texts of millions of Steam accounts, but account security wasn't compromises.