Qubic freezes chain after attacker drains 1.4K wallets with weak seeds

Layer-1 blockchain network Qubic halted operations Sunday after an attacker reportedly exploited weakly generated wallet seeds to drain approximately $1.4 million from more than 1,400 accounts, according to the project. 

In a statement on X, Qubic said the network was halted at tick 85,371,949, where it remains paused at the time of writing. Qubic said the vulnerability affected wallet seeds generated using any browser on an iPhone or iPad, Safari on a Mac until Oct. 18, 2026, or the Qubic iOS app before July 2025, leading to 2.94 trillion Qubit (QU) stolen. 

“87.1% of the drained funds never left the Qubic network and remain frozen in place,” said Qubic. “The remaining 12.9% was sent to MEXC, whose team froze the receiving account within about an hour.” 

The Qubic theft is the latest in a series of attacks tied to weak wallet seeds. In July, Coldcard disclosed that attackers had stolen funds from wallets whose seeds were weakened by a firmware bug. Similar flaws affected Trust Wallet’s browser extension and the Libbitcoin Explorer tool in 2023.

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Qubic said it has fixed the seed-generation flaw in the latest version of its web wallet.