Pinterest detected suspicious activity on some of its accounts and asked its customers to log in with their Google account OR log in with their Facebook account OR reset their password.
The unauthorized login attempts were made to several Pinterest accounts that might have also contained Pins, boards and messages.
They however added additional monitoring systems to reduce the likelihood of further problems going forward but also recommend the users to sign up for two-factor authentication.
Source: https://www.databreaches.net/pinterest-notifies-users-of-suspicious-activity/
"id": "PIN233617123",
"linkid": "pinterest",
"type": "Data Leak",
"date": "12/2017",
"severity": "50",
"impact": "2",
"explanation": "Attack limited on finance or reputation"