EU Privacy watchdogs have sent letters to WhatsApp around its data sharing with owners Facebook, and Yahoo over its 2014 security breach.
In a letter sent to the firm, the authorities "requested WhatsApp to communicate all relevant information to the Working Party as soon as possible and urged the company to pause the sharing of users' data until the appropriate legal protections could be assured."
The Working Party also wrote to troubled former internet giant Yahoo over a large data breach which exposed the personal details of 500 million users. It also transpired at the time that Yahoo was scanning its users' incoming emails for data requested by US intelligence agencies.
"Yahoo was invited to provide information on the legal basis and the compatibility with EU law of any such activity," the Working Party said in a statement.
Both firms are also set to answer to new UK Information Commissioner Elizabeth Denham. In her first speech after taking the role, Denham said that the ICO would be questioning Yahoo about its catastrophic data breach, and is looking to probe WhatsApp and other Facebook-owned companies over how they share data with one another.
Both cases will come before EU regulators in November 2016.
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