SlowMist Says Qubic Wallet Keys Could Be Recovered From Six Network Samples

Security firm SlowMist says six consecutive values exposed in Qubic Wallet’s network requests were enough to reconstruct a private key in a local proof-of-concept, revealing a way to compromise accounts created with the wallet’s vulnerable seed generator.

In its analysis, the firm says the wallet used the non-cryptographically secure `Math.random()` function to generate account seeds—the secrets from which signing keys are derived. Outputs from the same random stream also appeared in a request-header field called `dejaVu`, readable by network peers. Predicting the seed would give an attacker control of the signing key without needing the user’s wallet password, according to SlowMist.

Qubic’s version 4.26.4 patch switches new seed creation to cryptographic randomness, breaking that shared-stream link. It leaves the header generator unchanged and does not replace previously generated seeds.

The research follows Qubic’s Oct. 18 disclosure that an attacker drained about 2.94 trillion QU from 1,404 wallets. The incident prompted a network halt, as The Defiant previously reported.

SlowMist’s test modeled the V8 JavaScript engine’s pseudorandom generator. The firm says a bridge, a peer, or an observer on the unencrypted bridge-to-peer connection could collect the header values. The wallet’s encrypted connection to the bridge would not protect that onward traffic.

The demonstration does not establish that this route was used in the reported theft. SlowMist calls the attack flow hypothetical and says real-world success depends on consecutive, correctly aligned observations and whether other calls to `Math.random()` interrupt the sequence.

New Seeds, Old Exposure

Qubic said version 4.26.4 corrected seed generation. The code replaces `Math.random()` with `crypto.getRandomValues()` in the Create Vault and Add Account seed-generation paths.

But the release’s dependency lockfile still pins the TypeScript library to version 0.1.5, whose header generator continues to use `Math.random()`. The patch changes the source of new signing secrets rather than removing the header output.

The immediately preceding web-wallet release, 4.26.3, contains the weak seed generator. SlowMist does not give a complete affected-version range or a count of exposed keys.

Qubic’s own affected-user warning covers seeds created in any browser on an iPhone or iPad before Oct. 18, 2026; in Safari on a Mac before that date; or in the Qubic iOS app before July 2025. That platform list should not be read as the scope of SlowMist’s V8-based demonstration.

For existing holders, changing the generator does not itself make an old seed unpredictable. Qubic has said a full technical report will follow once recovery is settled.