Blink halted its Bitcoin Lightning Network (Bitcoin's fast payment layer) app on September 19 after an attacker drained funds from a few dozen custodial wallets, where Blink held the private keys. Non-custodial users managing their own keys through the Spark protocol were unaffected, and Blink said Spark was not implicated. The company paused service, deployed an emergency patch and restored operations by Saturday evening, saying all affected accounts had been identified and would be made whole. Blink did not disclose the amount taken. It credited multisig cold storage (storage requiring multiple approvals) and smaller hot-wallet components with limiting the damage. The attack vector remains unconfirmed, while the incident adds to recent security and operational problems across Lightning applications and is likely to accelerate Blink's shift away from custodial services in some regions.