Qubic, the Layer-1 blockchain network, stopped producing blocks on October 18, 2026, after an attacker pulled roughly 2.94 trillion QU tokens — about $1.4 million — out of 1,404 wallets. The raid ran for about 104 minutes before validators, known on the network as Computors, halted the chain at tick 85,371,949.
The root cause wasn't a bug in the protocol. It was weak random seeds.
How the attacker got in
Weak random seeds are the kind of flaw that doesn't announce itself. If the numbers a system uses to generate keys or sign operations aren't random enough, an attacker can guess them, predict them, or reproduce them at scale. That's what happened here: the seeds weren't strong enough to keep the attacker out, and the drain touched more than 1,400 wallets before anyone pulled the plug.
The scope matters. This wasn't a single compromised key or a phishing campaign against one user. The attacker moved across a wide set of addresses in under two hours, which points to something automated and repeatable rather than a one-off hit.
Why Computors stopped the chain
Stopping a chain mid-exploit is a blunt instrument, and the Computors used it. Halting at tick 85,371,949 froze the network while the drain was still in progress, which cuts both ways: it likely limited further losses, but it also means the chain is down while the team works out what to do next.
Qubic hasn't said publicly whether the halt was coordinated in advance or triggered reactively as the losses stacked up. What's clear is that the decision came from validators, not from a central operator — Computors are the ones who keep the network running, and they're the ones who stopped it.
The seed problem is the hard part
Fixing a protocol bug is a known quantity: patch the code, ship it, get validators to upgrade. Fixing weak randomness is messier. Seeds sit underneath everything — key generation, signing, address derivation — and if the source of randomness was flawed, the question isn't just which wallets were hit. It's whether the same weakness can be exploited again after the chain restarts.
That's the unresolved piece. Qubic has confirmed the cause but hasn't laid out a remediation plan, and until it does, the 1,404 affected wallets aren't the only ones with something to worry about.
The network is still halted. The next concrete step is a restart, and the conditions for that restart haven't been published: whether the team will roll back state, compensate affected holders, or push a fix that changes how seeds are generated across the network. None of that is settled yet.
For now, the chain sits at tick 85,371,949, and the attacker's 104-minute window is closed. What happens when Qubic turns the network back on is the part nobody has answered.
