This article links to a Forbes article that states it was a leak of a Saleforce instance that contained contact information about small and medium businesses.
This PCWorld article seems to be taking that to mean that every single gmail account (2.5B) is at risk with nothing to support that claim.
I'm dubious. This requires you give google a phone number. Almost universally if you give a company a phone number there is eventually an avenue for an attacker to convince the company to give them control of the account by demonstrating control of the number (which they've sim swapped or otherwise hijacked).
Even if at the moment there is no avenue to exploit google this way (also doubtful), all it takes is some new product (like workspaces) that has a different security understanding or new bugs to open a vector.
I get the sense that there was a time when Google would have not have trusted an off-the-shelf solution like Salesforce, and would have built their own in-house thing.
The headline looks incorrect. This looks like a blogspam of a blogspam of the original Salesforce database hack reported a while ago, where Google Cloud customers had their company name and contact information stolen. This information is useful for phishing attacks on those Google Cloud customers. Free Gmail users wouldn't be in that database.
This PCWorld article seems to be taking that to mean that every single gmail account (2.5B) is at risk with nothing to support that claim.