Qubic: A Wallet Flaw on Apple Devices Let a Thief Empty 1,404 Accounts

At 23:42 UTC on Saturday 17 October 2026, someone began emptying Qubic wallets that did not belong to them. By 01:26 UTC on Sunday, an hour and 44 minutes later, 1,404 of them were bare. Within hours, the computers that run the Qubic network did something very few blockchains ever do. They stopped it.

Qubic is a small blockchain, a shared public ledger of who owns which coins, kept by computers around the world instead of by a bank. Its coin is called QU and trades on exchanges under the ticker QUBIC. The project was founded by Sergey Ivancheglo, a developer known online as Come-from-Beyond, who earlier co-founded IOTA and created NXT. Qubic describes itself as a network for artificial intelligence, and says its miners spend their computing power training AI. It made headlines in August 2025, when Ivancheglo claimed its mining pool had taken more than half the computing power behind Monero, a separate privacy coin, and Qubic's miners rewrote six Monero blocks. BitMEX Research doubted that Qubic ever held a real majority.

Qubic's own statement on X put the haul at "around 2.94 trillion QU". One QU is worth a tiny fraction of a cent, so trillions of them add up to about $1.3 million to $1.4 million. The range is a matter of timing, not of dispute. At the price CoinGecko recorded around the start of the theft, about $0.00000047 a coin, the stolen QU was worth roughly $1.39 million, and early reports from crypto.news and Cointelegraph used $1.4 million. On Sunday the QUBIC price fell more than 10%, according to Bitcoin.com, and at Sunday afternoon's price the same coins were worth about $1.26 million. Bitcoin.com, Crypto Briefing, The Defiant and Crypto Times reported $1.3 million. Qubic itself gave no dollar figure. The stolen coins came to about 2% of all QU in circulation.

A password that was not random

A Qubic wallet is opened with a seed: 55 lower-case letters that serve as the account number, the password and the proof of ownership all at once. Whoever has the seed owns the coins. There is no bank to call and no reset button. If every letter is truly picked at random, the number of possible seeds runs to 78 digits, far too many for any computer to guess.

The letters were not picked at random enough. "Some wallet seeds were generated with insufficient randomness, making them weaker than they should be," Qubic said. "The attacker exploited this to access the affected wallets. The issue was in seed generation, not in the Qubic protocol itself." In stock-market terms, the exchange itself was not broken into. The thief got in through the login codes that one of the broker's apps had been handing out.

Qubic's public code shows where the weakness sat. Until 18 October its web wallet chose each of the 55 letters with Math.random, a function built into every web browser. Math.random is the browser's dice for games and animations. Mozilla's developer documentation warns that it is not secure and should not be used for anything to do with security. At 03:28 UTC on 18 October, a Qubic developer committed a change titled "fix: use cryptographically secure seed generation", which swapped Math.random for crypto.getRandomValues, the browser tool made for passwords and keys. It shipped as wallet version 4.26.4 about half an hour later.

Qubic named three groups of exposed seeds:

Seeds made on an iPhone or iPad, in any browser, before 18 October 2026.

Seeds made on a Mac using Safari, before 18 October 2026.

Seeds made in the Qubic iOS app, before July 2025.

The Apple link explains the "any browser" line. Outside the European Union, Apple requires every browser on an iPhone or iPad to run on its own WebKit engine, so Chrome or Firefox on an iPhone was running the same code as Safari. Qubic has not explained why seeds made in Apple's software turned out to be guessable while those made elsewhere apparently did not, and has promised a full technical report. The fix protects only new seeds. An old weak seed stays weak, and its owner has to create a new wallet and move the coins across, which nobody can do while the network is stopped. Qubic's developers say they found and secured other exposed funds before the attacker reached them.

Switching the whole network off

Qubic is run by 676 Computors, the validators that check and confirm every transaction, much as a clearing house settles trades between brokers. Under the network's rules, 451 of them, two-thirds plus one, make binding decisions. On 18 October they "coordinated a protective halt of the network at tick 85,371,949", Qubic said. A tick is Qubic's word for a block, one page of the ledger. "No transactions are processing, so the drained funds cannot be moved or sold while this is resolved."

The halt freezes everyone, not only the thief. Every QU holder is locked out, the way a stock exchange suspending all trading stops honest investors as well as the one under investigation. QEARN, Qubic's savings scheme in which holders lock up coins to earn more, was not touched by the theft, according to Bitcoin.com and Crypto Briefing, but it is frozen along with everything else.

"87.1% of the drained funds never left the Qubic network and remain frozen in place," Qubic said. That is about 2.56 trillion QU. "The remaining 12.9% was sent to MEXC, whose team froze the receiving account within about an hour." That share, about 379 billion QU, is worth roughly $170,000 at current prices. MEXC, at Qubic's request, and Bitget both suspended QUBIC deposits and withdrawals on 18 October, and the smaller exchange XT did the same, citing wallet maintenance.

The word "frozen" needs care. The coins on the Qubic network are stuck because the network is stopped, not because anyone has taken them back. The attacker's wallets still exist and still hold the coins. If the network restarted with no decision about them, they could move again.

Who decides what happens to the money

"Any resolution is a decision for the Computor quorum, under the rules of the network," Qubic said. Its core team is identifying every affected wallet and preparing options for the Computors to vote on, and a community poll is running on Discord to show them where holders stand. It is something like a shareholder vote on whether to undo a set of trades, except that the voters also run the market. Qubic has not published the options.

Other networks have faced the same choice. Ethereum rewrote its history in 2016 to undo the theft from The DAO, and split in two over it. In 2026 Harmony deleted a day of transactions to undo a forgery, Ravencoin's mining pools chose which four days of history to erase, and Cronos halted its chain during the Tectonic attack. Each time, the money was saved only by admitting that a small group could change the ledger.

Qubic has told victims to report the theft to the police or to cybercrime authorities in their own country, with the wallet ID, the amount lost and the transaction link from its explorer. "Formal reports help exchanges keep funds frozen," it said. It also warned that "Nobody from Qubic will ever message you first, ask for your seed, or offer recovery services for a fee." Fake recovery services are a common second robbery for people who have just lost money.

Weak seeds have emptied wallets before. In 2023 a flaw in the Libbitcoin Explorer tool, known as Milk Sad, cost users more than $900,000, and a Trust Wallet browser extension bug cost about $170,000. In 2026 thieves guessed keys made by the Ill Bloom code library and by Coldcard devices. The pattern is the same each time. The code worked, the coins were real, and the randomness that was meant to protect them was not.