Data breach victims can sue Yahoo in the United States.
Data breach victims can sue Yahoo in the United States.

A federal judge in California Friday ruled Yahoo must face many of the claims brought against it in a lawsuit concerning the massive data breaches affecting 3 billion users that the company announced in 2016.

U.S. District Judge Lucy Koh rejected a bid from Verizon Communications, Inc., which bought Yahoo in June, to dismiss several claims including negligence and breach of contract. The Plaintiffs accused of being too slow to disclose the breaches and thus increased the user's risk of identity theft and requiring them to spend money on credit freeze, monitoring and other protection services.  

Seeking to dismiss these claims, Yahoo said it has long been the target of “relentless criminal attacks,” and that the plaintiffs' “20/20 hindsight” did not cast doubt on its “unending” efforts to thwart “constantly evolving security threats,” according to court documents.

Judge Koh said the "Plaintiffs' allegations are sufficient to show that they would have behaved differently had defendants disclosed the security weaknesses of the Yahoo Mail System."