Yahoo disclosed that data breach on their User Accounts. This data breach contains several users personal information.
Yahoo's Chief Information Security officer Bob Lard says
The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. The investigation indicates that the stolen information did not include passwords in clear text, payment card data, or bank account information. Payment card data and bank account information are not stored in the system the company believes was affected
The affected user should change their passwords and security question.
More Details : https://yahoo.tumblr.com/post/154479236569/important-security-information-for-yahoo-users