Nearly two weeks of data were publicly available 267 million Facebook users

Attackers can use this data for spam and phishing.
According to the source, a database with records of 267,140,436 Facebook users, most of whom are from the United States, was available for download at one of the hacker forums from December 4 to 19.

Each entry included basic data, such as the full name and phone number, as well as the identifier of the account by which profile data can be obtained.

Presumably, the data was collected using scripts viewing the pages of a social network, or using a vulnerability in the Facebook API.

As soon as the provider was notified about the database on whose servers it was located, it was deleted. Attackers who managed to download the database can use the data contained in it for spam and phishing.