Coldcard Breach: Why Hardware Wallets Are a Myth

The estimated Coldcard Bitcoin loss has more than doubled, now standing at $70.2 million, signaling an escalating risk in hardware wallet security.

The Headline Number

This figure represents a substantial increase from initial estimates and underscores the severity of the firmware bug identified in Coldcard wallets. The re-evaluation by Galaxy Research points to a broader impact, indicating that the initial assessment severely underestimated the scope and financial implications for affected users. For investors and institutions holding significant Bitcoin, such a rapid escalation in estimated losses from a single security flaw is a stark reminder of persistent risks in digital asset storage.

3 Key Findings

Finding 1: Expanded Scope of Loss

Galaxy Research identified 1,196 addresses that collectively lost 1,082.65 Bitcoin in a 41-minute window. This finding significantly expands the scale of the incident, more than doubling the prior estimate of 594.48 Bitcoin moved by AnchorWatch CEO and co-founder Rob Hamilton.

Finding 2: Coordinated Attack Pattern

Galaxy Research noted that the identified transactions shared a common pattern, including identical 30 satoshis per virtual byte fees and no change outputs. This distinct on-chain fingerprint suggests a coordinated exploitation of the firmware bug, although future attacks might evolve beyond this pattern.

Finding 3: Delayed Advisory and Vulnerability

The illicit Bitcoin movements occurred between 1:10 AM UTC and 1:51 AM UTC on July 30, across blocks 960,183 to 960,191. This was approximately 30 hours before Coldcard published its initial security advisory, highlighting a critical window where users remained exposed. Coinkite co-founder Rodolfo Novak acknowledged responsibility and the release of a hotfix.

What the Data Really Says

The increasing estimates of the Coldcard Bitcoin loss underscore a critical reality in the digital asset space: the “Fintech Disruption” trend brings both innovation and amplified risks. The initial analysis by AnchorWatch CEO Rob Hamilton, which pinpointed 594.48 Bitcoin (worth $38 million) across 500 transactions in a three-block window, was a starting point. However, Galaxy Research’s more extensive tracing across 1,196 addresses over a 41-minute window to blocks 960,183 to 960,191, resulting in $70.2 million lost, indicates that comprehensive on-chain analysis is essential for accurately assessing incident impact. This expansion reveals how quickly and broadly a single vulnerability can be exploited.

Our read is that the delay in public disclosure, with Coldcard’s advisory coming 30 hours after the observed transactions, exacerbates the problem. While Coinkite has released a hotfix, the vulnerability of seeds generated on earlier firmware versions remains a concern. This incident highlights the profound operational and reputational risks for hardware wallet providers like Coldcard and their parent company, Coinkite. For the broader digital asset custody ecosystem, it signals the imperative for stringent security auditing, rapid response protocols, and transparent communication with users.

Methodology Note

Implications for CFOs and Finance Leaders

• Re-evaluate Custody Solutions: Assess the security architecture and incident response capabilities of all digital asset custodians, prioritizing solutions with transparent security audits and established track records. The expanding Coldcard Bitcoin loss serves as a direct case study.
• Enhance Due Diligence: Conduct deeper technical due diligence on hardware wallet providers, scrutinizing firmware update processes, bug bounty programs, and vulnerability disclosure policies.
• Implement Multi-Layered Security: Beyond hardware wallets, consider multi-signature schemes, offline cold storage for larger holdings, and diversified custody providers to mitigate single points of failure.
• Demand Transparency: Expect clear and timely communication from service providers regarding security incidents. Delays in advisories can significantly amplify financial and reputational damage.

The Bottom Line

Frequently Asked Questions

What caused the Coldcard Bitcoin loss?

The Coldcard Bitcoin loss was attributed to a firmware bug that created a software fallback path, allowing for unauthorized access to funds. Coinkite co-founder Rodolfo Novak acknowledged the vulnerability and released a hotfix to address it.

How was the updated loss figure determined?

Galaxy Research, the research arm of Galaxy Digital, conducted an in-depth on-chain analysis. They traced 1,196 addresses and identified common transaction patterns, including identical fees and no change outputs, to expand the scope of the affected funds to 1,082.65 Bitcoin.

What steps should Coldcard users take now?

Coinkite has released a hotfix to remove the software fallback path. Users should ensure their Coldcard devices are running the latest firmware version. However, Rodolfo Novak warned that this update does not protect seeds generated on previously vulnerable firmware, so users should assess their specific generation date.