Hackers have absconded with more than $100 million worth of Bitcoin from thousands of supposedly secure accounts in recent days, setting up another scandal for investors who have been repeatedly preyed upon by thieves in the sector.

The latest missing money stems from a software flaw in what’s known as a “cold” Bitcoin wallet hosted by Canada-based Coinkite Inc. Cold wallets have physical hardware associated with them alongside private passwords, or “keys,” intended to add an extra layer of security beyond the typical lengthy codes that nonetheless frequently get hacked.