Qubic Hack: Seed Phrases Made in iPhone Browsers Were Guessable, 1,404 Wallets Drained, Chain Frozen

Between 23:42 UTC on October 17 and 01:26 UTC on October 18, 2026, an attacker emptied 1,404 wallets on the Qubic network, moving about 2.94 trillion QU, worth roughly $1.3 million at the time. The Qubic hack did not touch the protocol, the validators or any smart contract. It exploited the way some wallets had created their recovery seeds: the web wallet used a general-purpose random number generator, and on Apple devices the result was predictable enough to reproduce. The network's operators halted the chain at tick 85,371,949, 87.1% of the stolen tokens are frozen in place, the rest sits in a frozen account on the MEXC exchange, and the restart date is unknown. One early report put the loss above $100 million; at the token's price that night the stolen amount was about a hundredth of that. Here is what broke, who was exposed, what happens to the frozen funds and why this is the third weak-seed incident of its kind in three years.

Key takeaways

• The attack ran 104 minutes, drained 1,404 wallets and moved about 2.94 trillion QU, roughly $1.3 million; the token fell about 11% on the day.
• Root cause: the Qubic web wallet generated seeds with JavaScript's Math.random() instead of a cryptographic generator; the fix in version 4.26.4 swaps it for crypto.getRandomValues().
• Exposed seeds were created in any browser on an iPhone or iPad before October 18, 2026, in Safari on a Mac before the same date, or in the Qubic iOS app before July 2025.
• Computors, the fixed quorum that runs the network, stopped the chain and will vote on a recovery plan; 87.1% of the funds never left the network and 12.9% were frozen by MEXC within about an hour.
• The same bug family emptied Coldcard wallets of 594 BTC in July 2026 and Libbitcoin Explorer users of more than $900,000 in 2023: a seed is only as strong as the randomness behind it.

What happened, hour by hour

The project says it also moved funds from other wallets that shared the weakness before the attacker could reach them, and that QEARN, the network's staking feature, was not affected. A full technical report is promised after the recovery plan is settled.

Why the Qubic hack was a seed problem, not a chain problem

A seed is the secret from which every private key in a wallet is derived. Anyone who knows the seed controls the funds. The whole design rests on one assumption: the seed came from a source nobody can predict. The industry standard is 128 bits of entropy, a number so large that guessing is hopeless.

Math.random() was never built for that job. It is a convenience generator for games and animations, with a small internal state and no guarantee about where that state starts. If the starting point is drawn from a narrow range, the attacker does not need to guess 128 bits; they need to enumerate the possible starting points, run the same code and check which resulting seeds unlock wallets with a balance. That is why 1,404 wallets fell in under two hours: nobody phished 1,404 people. Someone regenerated their seeds.

Qubic's own description is narrower than "all web wallets". The predictable output showed up in seeds generated in any browser on an iPhone or iPad, in Safari on a Mac, and in the old Qubic iOS app. Why the same code behaved worse on Apple's browser engine than elsewhere is something the project has left for its technical report. The GitHub commit for version 4.26.4 shows the fix: Math.random() replaced by crypto.getRandomValues(), the browser's cryptographically secure generator, which is what a wallet should have used from day one.

Who was exposed and who was not

Affected, according to Qubic:

• Seeds created before October 18, 2026 in any browser on an iPhone or iPad.
• Seeds created before October 18, 2026 in Safari on a Mac.
• Seeds created before July 2025 in the Qubic iOS app.

Not affected: seeds created on other platforms, hardware-generated seeds imported into the wallet, and QEARN staking positions. The project is identifying affected wallets itself and advises victims to file a police report in their own country with the wallet ID, the amount lost and a link to the transaction in the Qubic explorer. A poll on the project's Discord is collecting community views on how and when compensation should work.

Frozen funds and the Computors' vote

Qubic does not use miners or a conventional validator set. Transactions are processed by Computors, a fixed group of operators that act as a quorum and vote on network decisions; progress is measured in ticks rather than blocks. Stopping the chain is therefore a decision a known group can take in minutes, which is exactly what happened at tick 85,371,949. While the chain is paused, 87.1% of the stolen QU cannot move. The remaining 12.9% reached MEXC, whose compliance team froze the receiving account on suspicion that it was tied to the attack.

The next step is a vote among Computors on recovery options prepared by the core team. The practical choices are the same every frozen chain faces: roll back the affected transfers, reassign the frozen balances to the original owners, or leave the ledger as it is and compensate victims from a treasury. The ability to do any of this is also the lesson of the week for anyone who believed the network was ungovernable. We saw the exchange side of the same power when an exchange account freeze hit users who had done nothing wrong.

The same bug family: Coldcard, Milk Sad, Trust Wallet

The Qubic hack belongs to a short and expensive list of weak-seed incidents.

• Coldcard, July 31, 2026: a firmware build from 2021 produced guessable seeds on an air-gapped hardware wallet. About 500 addresses lost 594.48 BTC, around $38 million, in 25 minutes, and the running total later passed $130 million. Our reconstruction of the Coldcard firmware entropy bug walks through the night and the disclosure.
• Milk Sad, 2023: Libbitcoin Explorer 3.x seeded its generator with 32 bits of system time, giving attackers a few billion candidates to try. More than $900,000 was stolen from roughly 2,600 wallets before the disclosure (CVE-2023-39910).
• Trust Wallet, 2023: a weakness of the same type in the browser extension's seed generation was tracked as CVE-2023-31290 and documented by Ledger's security team.

What these cases share is that the user did everything right. No phishing link was clicked, no seed was typed into a fake site, no malware like the OkoBot stealer was involved. The failure was upstream, in the code that produced the secret. That is why the question "where did this seed come from" matters as much as "where is it stored", a point our guide to hardware wallet security makes in detail.

What Qubic is and why the project is familiar

Qubic is a layer-1 network founded by Sergey Ivancheglo, a co-founder of IOTA. It processes transactions and smart contracts without fees and runs on what it calls Useful Proof of Work: miners' hardware is pointed at computations the project considers useful, including training its own neural network, instead of pure hashing. The token trades as QUBIC on exchanges, with a market capitalization of about $62.6 million at the time of the incident; the on-chain unit is QU, which is why 2.94 trillion of them are worth seven figures rather than twelve.

The project made headlines in August 2025 for a different reason: its mining pool pointed its CPUs at Monero's RandomX algorithm, grew from under 2% of Monero's hashrate in May to more than 25% by late July, and then claimed to have crossed 51%. Ledger's chief technology officer called it a successful 51% attack in progress; Qubic called it an experiment and a stress test. The episode is part of the background to the delistings that shaped how XMR trades today. A project that demonstrated its ability to pressure another chain's consensus has now paused its own chain to undo a theft, which is at least consistent.

What to do if you hold QU, and what everyone else should take from it

• If your seed was created in one of the three listed environments, treat it as compromised even if the balance is intact. Once the network restarts, move funds to a wallet whose seed was generated by the fixed version or by a hardware device.
• Do not reuse the old seed for anything, and do not type it into any site that offers to "check" it; checkers that ask for a seed are the oldest scam in the book.
• Expect exchange deposits and withdrawals of QUBIC to stay suspended until the chain restarts. MEXC and Bitget both paused them on October 18.
• For every other wallet: prefer seeds generated by audited, open-source code or by a hardware device, and keep the generating software updated. A seed made by a browser tab is only as good as the function that tab called.
• Keep the Coldcard precedent in mind: even air-gapped devices had a generation flaw. Diversifying across wallet makers limits how much one bug can take.

Key terms

• Seed: the master secret from which a wallet derives all private keys; usually shown as 12 or 24 words.
• Entropy: the amount of unpredictability behind a secret, measured in bits; 128 bits is the industry minimum for seeds.
• Math.random(): JavaScript's general-purpose random number function, not designed for cryptographic secrets.
• crypto.getRandomValues(): the browser function that draws randomness from the operating system's cryptographic generator.
• Computors: the fixed set of operators that process Qubic transactions and vote on network decisions as a quorum.
• Tick: Qubic's unit of ledger progress, comparable to a block number.