The protocol wasn’t compromised—the wallet itself weakened its random numbers.
In its October 20 postmortem, SlowMist reported that the Qubic web wallet used JavaScript’s Math.random() to generate 55-character seeds, without mixing in users’ passwords or device entropy. From 23:42 UTC on October 17 to 01:26 UTC on October 18, attackers drained about 2.94 trillion QU from 1,404 addresses (worth roughly $1.3–1.4 million at the time).
More alarming was the data path: the same random stream also wrote dejaVu values into network headers, which were forwarded over plaintext TCP. SlowMist verified locally that six consecutive dejaVu values were enough to recover the generator state in about 15 milliseconds, then verify the seed against public keys in balance queries.
The affected scope is very specific: seeds generated before October 18 in any browser on iPhone/iPad, in Safari on Mac, and in iOS apps released before July 2025. On October 19, the official team switched to a cryptographically secure random source in web wallet 4.26.4. Old seeds are still unsafe—you need to create a new one and migrate.
The Computors halted the network at tick 85,371,949. About 87.1% of the stolen QU remains frozen on-chain, while roughly 12.9% went to MEXC. The exchange froze the receiving accounts within about an hour.
Official update from @_Qubic_ on October 20: Arbitration approved the recovery plan, the network is running again, and the claims site is open. The first verified addresses have already received refunds. The window is open until May 1, 2027; the only official site is weak-seed-reclaim.qubic.org. The team emphasizes: they will not DM you first, never share your seed, and they will not charge a “recovery fee”—treat any other links as phishing.
In short: insufficient seed entropy means that even halting the network can’t save the false sense of security offered by something that “looks long enough.”
This is not investment advice.