Coldcard RNG Flaw Weakened Wallet Seeds for Nearly Five Years

Key Point

Coldcard firmware used a predictable software pseudorandom number generator instead of the intended hardware source. A 2021 code migration introduced the flaw and weakened wallet seeds for nearly five years across several Coldcard models and firmware versions. The estimated search space fell to roughly 40 bits on Mk2 and Mk3 devices and about 72 bits on later models. Galaxy Research identified four suspected attack waves involving an estimated 5,294 addresses and 1,815.75 BTC. The figures do not represent individually verified victims or confirmed final losses, and the incident reflects a key-generation failure rather than a compromise of Bitcoin’s underlying cryptography.

Why it matters: Weak key generation may turn self-custody into a wallet-specific security risk even when the underlying blockchain remains secure.

Market Sentiment

Bearish, Stress-on, Tech-driven, Volatile.

Reason: A predictable wallet seed generator can weaken self-custody security, so traders may treat hardware-wallet trust as a live risk.

Similar Past Cases

In September 2022, Profanity vanity-address users faced private-key recovery attacks after a weakness in wallet generation, and attackers stole $3.3 million from affected Ethereum vanity addresses. (The Block) Difference: Profanity affected Ethereum vanity addresses, while the Coldcard incident concerns Bitcoin hardware-wallet seed generation.

Ripple Effect

Weak seed generation may propagate through wallet trust rather than protocol risk, because affected users must rotate funds into new seeds. If more clustered drains appear around the same seed-generation pattern, then market concern could broaden from one wallet maker to self-custody tooling.

Opportunities & Risks

Opportunities: If users can confirm that funds came from affected firmware, then moving funds to a new seed generated with patched firmware or another trusted environment reduces key-reuse risk.

Risks: If suspected attack waves continue to cluster around Coldcard-generated seeds, then reducing exposure to unchanged affected wallets limits loss risk while forensic uncertainty remains.