Qubic Halts Blockchain After Weak Seeds Drain $1.4 Million

Qubic halted its layer-1 blockchain Sunday after an attacker exploited weakly generated wallet seeds and took about 2.94 trillion Qubit (QU) tokens from more than 1,400 accounts. The network remains paused while the project reviews the theft and prepares recovery options.

In a post on X, Qubic reported that the network stopped at tick 85,371,949. The vulnerability affected seeds created with any browser on an iPhone or iPad, Safari on a Mac through Oct. 18, 2026, or the Qubic iOS app before July 2025.

About 87.1% of the stolen funds remained on the Qubic network and were frozen, according to the project. The other 12.9% was sent to cryptocurrency exchange MEXC. The exchange froze the receiving account about an hour later, Qubic reported.

Qubic fixed the seed-generation flaw in version 4.26.4 of its web wallet. The update replaced JavaScript’s Math.random() function, which is not designed to create cryptographic secrets, with crypto.getRandomValues(), a function intended for secure random-number generation.

The Qubic core team is identifying affected wallets and preparing recovery options for a vote by the network’s Computors. Those participants will decide what happens to the frozen funds. Qubic plans to publish a technical report after a recovery plan is settled. It has not announced when the blockchain will restart.

The incident follows other thefts linked to weak wallet seeds. Coldcard disclosed in July that attackers stole funds from wallets affected by a firmware bug. Similar seed-generation problems affected Trust Wallet’s browser extension and the Libbitcoin Explorer tool in 2023.

Qubic supports transactions and smart contracts without network fees. Its Useful Proof of Work consensus system uses mining energy to train artificial-intelligence models. The QU token had a market capitalization of about $62.6 million on Oct. 18, according to CoinGecko.