Qubic, a decentralized AI computing network, paused its mainnet on October 18, 2026, after an attacker drained 1,404 user wallets containing approximately 2.94 trillion QU tokens, valued at roughly $1.3 million at the time.
The developers attributed the exploit to weak, predictable wallet seeds generated on legacy Apple devices, Safari browsers, and early iOS applications, rather than a vulnerability in the network's core code itself.
Timeline and Response
The attack occurred between 23:42 UTC on October 17 and 01:26 UTC on October 18, spanning approximately 1 hour and 44 minutes. Validators halted the chain at tick 85,371,949, Qubic's unit of network progress comparable to blocks on other blockchains.
Of the drained tokens, 87.1% remained immobilized on-chain and unable to be moved or sold. The remaining 12.9% reached MEXC, which froze the receiving account within one hour on suspicion of its connection to the attack. Bitget suspended all QUBIC deposits and withdrawals as a precaution.
Remediation
Qubic's team released client version 4.26.4 to address the seed-generation weakness. Developers also secured additional funds exposed to the same vulnerability before they could be targeted. The network's staking feature, QEARN, was not affected by the incident.
Broader Context
This marks the second security incident affecting Qubic's peripheral systems in 2026. In August 2026, the Vottun Bridge was exploited, exposing operational risks tied to the network's outer components.
Qubic operates on a no-premine, fee-less model designed for running AI workloads with its native QU token. The network's Computor cluster, comprising operators who run the network and vote on its direction, will determine whether affected users receive compensation.
What Comes Next
Key developments to monitor include the Computor cluster's compensation vote, the timeline for restarting the mainnet on the patched 4.26.4 client, and when Bitget restores deposits and withdrawals. MEXC's handling of the frozen account will also indicate how exchanges coordinate on returning stolen funds.
