Cory Klippsten was at a wedding in Paris when the messages started coming in. "It was a brutal weekend for so many who lost bitcoin," the CEO of Swan said in an interview. "I was sending messages at 4 a.m. to help someone on Pacific Time get their coins to safety." That was last Thursday, when attackers began draining bitcoin from thousands of Coldcard hardware wallets, exploiting a firmware flaw that had sat undetected for five years. Swan, a U.S.-based platform that helps individuals buy, hold and self-custody bitcoin, paused withdrawals for at-risk clients, shipped in-app warnings and opened its migration support well beyond its user base.