XKEYCHAINX LABS
Coldcard / Public disclosure

Donjon full Mk3 extraction chain

A complete seed was recovered from a challenge wallet.

Source date: 2023 (presentation)Reviewed: 11 October 2026

Affected scope

Mk3 challenge wallets

What the attack requires

Physical possession; combined secure-element and MCU laboratory attacks.

Response & remediation

What changed

Later architecture changes do not retrofit Mk3.

What this finding establishes

This is the practical continuation of a 2021 research line, presented in 2023. It is separate from the 2026 seed-generation incident.