Fastly says single customer triggered bug behind mass internet outage

Flaw was introduced in May and lay dormant until a customer updated their settings, firm says

An internet blackout that knocked out some of the world's biggest websites on Tuesday was ultimately caused by a single customer updating their settings, the infrastructure provider Fastly has revealed.

A bug in Fastly's code introduced in mid-May had lain dormant until Tuesday morning, according to Nick Rockwell, the company's head of engineering and infrastructure. When the unnamed customer updated their settings, it triggered the flaw, which ultimately took down 85% of the company's network.