Yahoo victims right to sue following Data Breaches

Hot on the heels of my last blog post, a judge in the US has ruled that victims have the right to sue Yahoo for claims of breach of contract and unfair competition!

Court Ruling

In her ruling, Californian US District Court Judge Lucy Koh has rejected claims by Yahoo that these individuals lacked grounds to sue the company.

Judge Koh found that because each affected user now faces the risk of identity theft, plaintiffs can now amend previously dismissed complaints.

Multiple Breaches and Leaked Data

There was in fact a total of 3 data breaches, 2013, 2014, and 2016:

  • 2013 – 1 billion+ accounts affected
  • 2014 – 500 million +accounts affected
  • 2015-2016 – 200 million+ accounts affected

Information exposed from each account, through these breaches could include:

  • Names
  • Email addresses
  • Telephone numbers
  • Security questions, and answers
  • Dates of Birth
  • Password hashes


Controversially, Yahoo chose not to disclose these earlier breaches until well after the event.  The timing of the disclosure is also attributed to a reduced closing price when Verizon acquired Yahoo in a deal which closed in June 2017 and was worth circa $4.8 billion US dollars.