Verify a decision

{"actor":"system:backfill","investigation_id":"84169ff4-2482-46ea-a403-5e6d11b5db7d","kind":"publish","page_slug":"coldcard-coinkite-hardware-wallet-exploit","published_at":"2026-09-23T17:05:34.444Z","sequence_num":1,"snapshot":{"content_type":"investigation","entity_name":"Coldcard (Coinkite Hardware Wallet Exploit)","sections":[{"content":"Coldcard is a Bitcoin-only hardware wallet developed and sold by Coinkite Inc., a company headquartered in Toronto, Ontario, Canada. Co-founded by Rodolfo Novak (CEO) and Peter Gray (CTO), Coinkite has marketed Coldcard as one of the most security-focused hardware wallets available, emphasizing open-source firmware, air-gap operation, and no reliance on proprietary companion software. The device was widely recommended within Bitcoin self-custody communities and adopted by security-conscious holders globally. Coldcard models include the Mk2, Mk3, Mk4, Mk5, and Q series. The device stores BIP-39 seed phrases offline and is designed so that private keys never leave the device.","heading":"Background: Coldcard and Coinkite","severity":"low","sources":[{"credibility":1,"name":"CBC News — What we know about the ongoing Coldcard hack","type":"news_article","url":"https://www.cbc.ca/news/world/bitcoin-coinkite-security-hack-9.7295582"},{"credibility":1,"name":"Fortune — Bitcoin owners rocked by $116 million hack","type":"news_article","url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/"}]},{"content":"A build configuration error introduced in firmware version 4.0.0 (released March 17, 2021) caused seed generation on Coldcard devices to bind to MicroPython's software Yasmarang pseudorandom number generator (PRNG) instead of the STM32 hardware true random number generator (TRNG). The error originated in the libngu cryptographic library: libngu's preprocessor check tested only whether the macro MICROPY_HW_ENABLE_RNG was defined, not whether its value was nonzero. Because Coldcard's production build defined that macro as zero (to disable MicroPython's own hardware RNG path, as Coldcard used a separate implementation), the check evaluated as if hardware RNG was present — and the build silently fell back to the Yasmarang software fallback. Prior to firmware v4.0.0, seed generation used ckcc.rng_bytes(), which directly invoked the STM32 hardware TRNG. The change to ngu.random.bytes() introduced the flaw. The Yasmarang generator initializes from the chip's low 32 bits of unique ID XORed with SysTick and RTC time registers — all non-cryptographic, observable, or reconstructable values — and produces a deterministic stream thereafter with no further entropy collection. On Mk2 and Mk3 devices running versions 4.0.0 through 4.1.9, effective seed entropy collapsed to approximately 40 bits or fewer. On Mk4, Mk5, and Q models (firmware v5.0.0 onward), a secure element contributed 40 bytes that were subsequently hashed and used to reseed only a single 32-bit Yasmarang state word, limiting effective entropy to approximately 72 bits — substantially below the 128 bits users expected. Fixed firmware was released on July 31, 2026: version 4.2.0 for Mk2/Mk3, 5.6.0 for Mk4/Mk5, and 1.5.0Q for the Q model, with subsequent hardened releases 5.6.1 and 1.5.1Q following after a three-week post-incident audit. Critically, updating firmware does not retroactively repair an existing seed; affected users must migrate funds to a newly generated wallet on patched firmware.","heading":"The Firmware Vulnerability: Root Cause","severity":"critical","sources":[{"credibility":2,"name":"Block Engineering Blog — Predictable RNG Fallback and 32-Bit Reseed in COLDCARD Firmware","type":"research","url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"credibility":1,"name":"Coinkite Official Security Advisory — Coldcard Mk3 Seed Generation Warning","type":"official","url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/"},{"credibility":2,"name":"crypto.news — Coldcard hack: how a build flag drained $116M in bitcoin","type":"news_article","url":"https://crypto.news/coldcard-hack-bitcoin-self-custody-entropy/"},{"credibility":2,"name":"TRM Labs — The Largest Hardware Wallet Exploit of 2026","type":"research","url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"}]},{"content":"According to reporting by Phemex and others, Bitcoin developer James O'Beirne raised concerns about the flawed randomness code with Coinkite in May 2025 — approximately 14 months before active exploitation began. According to these reports, Coinkite CTO Peter Gray responded with an argument from absence rather than a technical rebuttal: that if such a flaw were real, it would likely have already surfaced through observed losses. Researchers and legal commentators have noted this reasoning was fundamentally flawed, because low-entropy key generation produces wallets that appear normal to owners while remaining silently vulnerable to offline brute-force enumeration; affected holders have no mechanism to detect compromised keys until funds are swept. Coinkite disputes the characterization that the warning was dismissed without investigation, but has not published a detailed account of its internal response to O'Beirne's communication. These allegations are drawn from third-party reporting and have not been adjudicated. Coinkite has not publicly confirmed or denied the substance of the reported exchange.","heading":"Prior Warning and Alleged Disclosure Failure","severity":"high","sources":[{"credibility":2,"name":"Phemex — Coinkite Was Warned 14 Months Early About the Coldcard Flaw","type":"news_article","url":"https://phemex.com/academy/coldcard-security-flaw-warning"},{"credibility":2,"name":"Cryptopolitan — Coinkite CTO Peter Gray linked to the code behind the $114M Coldcard hack","type":"news_article","url":"https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/"},{"credibility":3,"name":"Bitcoin World — Coinkite CTO Accused of Ignoring Prior Warning on Coldcard Code Flaw","type":"news_article","url":"https://bitcoinworld.co.in/coinkite-cto-ignored-warning-coldcard-flaw/"}]},{"content":"The exploitation of affected Coldcard wallets proceeded in at least four waves beginning July 30, 2026. Wave 1 (July 30, 2026) was the largest single sweep: an attacker drained approximately 1,082.65 BTC (roughly $70.2 million at the time) from about 1,196 addresses in approximately 41 minutes. On-chain analysis by Galaxy Research found the attacker targeted the largest balances first, extracting more than $30 million in the opening ten minutes. Wave 2 (July 31, 2026) swept approximately 594 BTC (~$38 million) from roughly 500 wallets in about 25 minutes. Waves 3 and 4 followed over subsequent days, draining approximately 208 additional BTC from nearly 2,000 further addresses. Total confirmed losses across all waves: approximately 1,816 BTC worth approximately $116 million, affecting over 5,200 addresses. An extended estimate cited by CBC News and Galaxy Research placed potential total losses at up to 2,055 BTC from approximately 7,300 addresses if additional suspected waves are confirmed. Differences in transaction construction across the four waves, noted by TRM Labs, suggest multiple attackers may have been involved rather than a single actor. No physical access to any device was required; all exploitation occurred through offline enumeration of the weakened seed space. The attack methodology involves deriving candidate seeds from the constrained entropy space, generating their corresponding Bitcoin addresses, and checking those against public blockchain data — a process executable on GPU clusters within days given the effective entropy levels.","heading":"The Exploit: Attack Timeline and Scale","severity":"critical","sources":[{"credibility":2,"name":"TRM Labs — The Largest Hardware Wallet Exploit of 2026","type":"research","url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"},{"credibility":1,"name":"CoinDesk — Major bitcoin wallet flaw drains 594 BTC in 25-minute sweep","type":"news_article","url":"https://www.coindesk.com/tech/2026/07/31/major-bitcoin-wallet-flaw-drains-594-btc-in-25-minute-sweep"},{"credibility":2,"name":"The Hacker News — Coldcard Hardware Wallet Flaw Linked to $70 Million Bitcoin Theft in 41 Minutes","type":"news_article","url":"https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to/"},{"credibility":1,"name":"CBC News — What we know about the ongoing Coldcard hack","type":"news_article","url":"https://www.cbc.ca/news/world/bitcoin-coinkite-security-hack-9.7295582"},{"credibility":1,"name":"Fortune — Bitcoin owners rocked by $116 million hack","type":"news_article","url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/"}]},{"content":"All Coldcard models that generated seeds between March 2021 and the July 2026 patch release are considered potentially compromised. Specifically: Mk2 and Mk3 devices running firmware 4.0.1 through 4.1.9 carry the worst exposure, with effective entropy as low as 40 bits. Mk4, Mk5, and Q models with seeds generated before version 5.6.0 (Mk4/Mk5) or 1.5.0Q (Q) carry reduced exposure of approximately 72 bits, which remains below the intended 128-bit security level and is theoretically brute-forceable against a targeted victim. According to Coinkite's own advisory, users who supplied at least 50 independent private dice rolls during seed creation are considered safe from the RNG issue alone, as that user-supplied entropy would supplement and dominate the weak hardware contribution. Users who applied a strong, unique BIP-39 passphrase also had their effective security materially increased. Coinkite strongly advised all holders who generated seeds on affected firmware to migrate funds to a new wallet immediately. Updated firmware: 4.2.0 (Mk2/Mk3), 5.6.0 and later 5.6.1 (Mk4/Mk5), 1.5.0Q and later 1.5.1Q (Q).","heading":"Affected Device Models and User Mitigation","severity":"critical","sources":[{"credibility":1,"name":"Coinkite Official Security Advisory","type":"official","url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/"},{"credibility":2,"name":"Block Engineering Blog — Predictable RNG Fallback and 32-Bit Reseed in COLDCARD Firmware","type":"research","url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"credibility":2,"name":"Coldcard Hack Explained — CryptoTimes","type":"news_article","url":"https://www.cryptotimes.io/learn/what-is-coldcard-hack/"}]},{"content":"As of early August 2026, the majority of stolen funds had not moved from attacker-controlled consolidation addresses. TRM Labs reported that roughly 90% of the stolen BTC remained stationary, with the largest individual attacker address holding approximately 1,159 BTC across seven addresses. Limited laundering activity was detected: a single Wasabi Wallet deposit of 64.9 BTC and a transfer of 200 ETH to Tornado Cash, both on August 4, 2026. The Tornado Cash transfer involved Bitcoin converted to ETH via THORChain before mixing. Approximately 600 flagged addresses were circulated to law enforcement agencies and cryptocurrency exchanges by blockchain intelligence firms. Crystal Intelligence and TRM Labs published tracing analyses. The absence of aggressive layering or mixing led TRM to note the pattern is atypical of professional cybercriminal groups such as the Lazarus Group.","heading":"On-Chain Tracing and Laundering Activity","severity":"high","sources":[{"credibility":2,"name":"TRM Labs — The Largest Hardware Wallet Exploit of 2026","type":"research","url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"},{"credibility":2,"name":"CryptoTimes — Coldcard Hacker Swaps Bitcoin to ETH via THORChain and Tornado Cash","type":"news_article","url":"https://www.cryptotimes.io/2026/08/05/coldcard-hacker-swaps-bitcoin-to-eth-via-thorchain-and-tornado-cash/"},{"credibility":2,"name":"Crystal Intelligence — Tracing the Coldcard hack: where the stolen Bitcoin went","type":"on_chain","url":"https://crystalintelligence.com/investigations/coldcard-exploit-tracing-stolen-bitcoin/"}]},{"content":"Coinkite issued a security advisory on July 30, 2026, the same day the first wave was detected. CEO Rodolfo Novak published a public apology on July 31, stating 'I'm sorry and I'm devastated' and acknowledging that the company accepted full responsibility for the firmware failure. Novak stated that the company's internal review process had failed to catch the error and that the company would publish a full technical post-mortem after verifying details. Coinkite also confirmed it would assist affected users seeking police reports, insurance claims, or independent investigations. Patched firmware was released for all affected models by July 31 for the initial emergency fixes, with hardened follow-up releases (5.6.1, 1.5.1Q) published approximately three weeks later following a comprehensive system-wide audit. Separately, Coinkite reversed a prior policy of automatically deleting customer records, citing anticipated legal obligations arising from the incident. Coinkite's advisory stated that 'The COLDCARD devices themselves were not hacked, remotely accessed, or taken over,' emphasizing that the exploit targeted weak seeds generated by the vulnerable firmware rather than any remote compromise of deployed devices. Bitcoin Magazine reported that Coinkite suggested the vulnerability may have been discovered by the attacker through AI-assisted code analysis of the open-source firmware, though the actual attack discovery method has not been confirmed.","heading":"Coinkite's Response","severity":"medium","sources":[{"credibility":1,"name":"Coinkite Official Security Advisory","type":"official","url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/"},{"credibility":2,"name":"Crowdfund Insider — Coldcard Issues Enhanced Firmware Update","type":"news_article","url":"https://www.crowdfundinsider.com/2026/08/300062-coldcard-issues-enhanced-firmware-update-amid-ongoing-bitcoin-btc-theft-fallout/"},{"credibility":2,"name":"Bitcoin Magazine — Coinkite Releases Fixed Firmware After Coldcard Bug; AI Likely Involved In The Breach","type":"news_article","url":"https://bitcoinmagazine.com/business/coinkite-releases-fixed-firmware-after-coldcard-bug-ai-likely-involved-in-the-hack"},{"credibility":2,"name":"Cryptopolitan — Coldcard overhauls data retention policy, prepares for legal obligations","type":"news_article","url":"https://www.cryptopolitan.com/coldcard-overhauls-data-retention-policy/"}]},{"content":"No arrest, charge, or fund seizure had been publicly announced as of early August 2026. According to Bitcoin Magazine, investigators traced on-chain sweep patterns to a paid account at a major blockchain data provider whose internal logs allegedly matched the theft workflow with unusual specificity, and relevant information was reportedly passed to law enforcement. The FBI has not made a public statement confirming or denying an active investigation. Spendnode and BitRss reported that the FBI may have identified suspects in the first-wave theft, but no charges have been filed. Approximately 600 flagged attacker addresses were shared with exchanges and law enforcement agencies by blockchain intelligence firms. Attribution of the broader incident to a specific actor or state-sponsored group has not been made publicly by any agency.","heading":"Law Enforcement and FBI Investigation","severity":"medium","sources":[{"credibility":2,"name":"Bitcoin Magazine — The Coldcard Hacker Left A Paper Trail That May Already Be In Law Enforcement Hands","type":"news_article","url":"https://bitcoinmagazine.com/technical/hunting-down-the-coldcard-hacker-wave-1-thief-may-be-known-to-fbi"},{"credibility":3,"name":"Spendnode — FBI May Have Identified First-Wave Coldcard Theft Attackers","type":"news_article","url":"https://www.spendnode.io/blog/fbi-identifies-coldcard-theft-attackers-august-2026/"},{"credibility":2,"name":"KuCoin Blog — Coldcard Bitcoin Hack: New Investigation Lead Emerges as 1,082 BTC Remains Unmoved","type":"news_article","url":"https://www.kucoin.com/blog/coldcard-bitcoin-hack-1082-btc"}]},{"content":"No class action lawsuit had been filed against Coinkite as of early August 2026. However, victims were reported to be preparing group litigation, and Coinkite itself cited 'ongoing and anticipated legal proceedings' when reversing its customer-data deletion policy. Legal analysis published by Canadian law firm WeirFoulds and aggregated by Mondaq and Lexology identified two potential recovery routes for victims: claims against Coinkite for damages arising from the defective product, and parallel crypto-tracing claims against parties that received stolen funds. Legal experts are reported to be sharply divided on the question of Coinkite's liability, with the company's terms of service and the open-source nature of the firmware among the contested factors. No court has ruled on any claim arising from this incident, and no finding of liability has been made.","heading":"Legal Exposure and Pending Class Action","severity":"medium","sources":[{"credibility":2,"name":"WeirFoulds — The Coldcard Exploit: Why Victims May Have Two Routes to Recovery","type":"other","url":"https://www.weirfoulds.com/the-coldcard-exploit-why-victims-may-have-two-routes-to-recovery"},{"credibility":2,"name":"Lexology — The Coldcard Exploit: Why Victims May Have Two Routes to Recovery","type":"other","url":"https://www.lexology.com/library/detail.aspx?g=fb177a37-2ba6-419e-9fc5-b337da7bae64"},{"credibility":2,"name":"Bitcoin.com News — Coinkite Faces Class Action Threat as Bitcoin Wallet Bug Costs Users Over 1,300 BTC","type":"news_article","url":"https://news.bitcoin.com/regulation-and-legal/coinkite-faces-class-action-threat-as-bitcoin-wallet-bug-costs-users-over-1300-btc/"},{"credibility":2,"name":"Cointribune — A class action is looming against Coinkite after the COLDCARD wallets hacking","type":"news_article","url":"https://www.cointribune.com/en/a-class-action-is-looming-against-coinkite-after-the-coldcard-wallets-hacking/"}]},{"content":"The incident triggered broad concern about hardware wallet security across the Bitcoin self-custody community. Glassnode reported that approximately 210,000 BTC moved by long-term holders in the days following the exploit, attributed in part to users auditing their own storage arrangements. Bitcoin and Ethereum prices declined less than 1% in the immediate aftermath. The incident prompted renewed debate among Bitcoin Core developers about the role of AI-assisted code auditing in security reviews, given the suggestion that an AI tool may have identified the flaw in the open-source firmware. The hack is classified by multiple sources as the largest cold-storage exploit on record and the third-largest cryptocurrency hack of 2026.","heading":"Market and Industry Impact","severity":"medium","sources":[{"credibility":2,"name":"BingX Flash News — Coldcard exploit triggers 210,000 BTC shift by long-term holders","type":"news_article","url":"https://bingx.com/en/flash-news/post/coldcard-hack-linked-to-m-theft-as-long-term-holders-move-btc-glassnode-says"},{"credibility":2,"name":"KuCoin Blog — Bitcoin Core Developers Debate AI Security After Coldcard Hack","type":"news_article","url":"https://www.kucoin.com/blog/bitcoin-core-ai-security-coldcard-hack-bug-reports"},{"credibility":2,"name":"IG UK — Coldcard Hardware Wallet Hack Drains $89M: What It Means","type":"news_article","url":"https://www.ig.com/uk/trading-strategies/coldcard-hardware-wallet-hack-self-custody-260803"}]}],"sources_used":[{"credibility":2,"name":"TRM Labs — The Largest Hardware Wallet Exploit of 2026","type":"research","url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"},{"credibility":1,"name":"Coinkite Official Security Advisory","type":"official","url":"https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/"},{"credibility":2,"name":"Block Engineering Blog — Predictable RNG Fallback and 32-Bit Reseed in COLDCARD Firmware","type":"research","url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"credibility":1,"name":"CoinDesk — Major bitcoin wallet flaw drains 594 BTC in 25-minute sweep","type":"news_article","url":"https://www.coindesk.com/tech/2026/07/31/major-bitcoin-wallet-flaw-drains-594-btc-in-25-minute-sweep"},{"credibility":2,"name":"The Hacker News — Coldcard Hardware Wallet Flaw Linked to $70 Million Bitcoin Theft in 41 Minutes","type":"news_article","url":"https://thehackernews.com/2026/08/coldcard-hardware-wallet-flaw-linked-to/"},{"credibility":1,"name":"Fortune — Bitcoin owners rocked by $116 million hack","type":"news_article","url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/"},{"credibility":1,"name":"CBC News — What we know about the ongoing Coldcard hack","type":"news_article","url":"https://www.cbc.ca/news/world/bitcoin-coinkite-security-hack-9.7295582"},{"credibility":2,"name":"crypto.news — A build error in Coldcard's firmware drained $38 million in bitcoin in 25 minutes","type":"news_article","url":"https://crypto.news/coldcard-firmware-bug-drains-38-million-bitcoin/"},{"credibility":2,"name":"crypto.news — Coldcard hack: how a build flag drained 116M in bitcoin","type":"news_article","url":"https://crypto.news/coldcard-hack-bitcoin-self-custody-entropy/"},{"credibility":2,"name":"Phemex — Coinkite Was Warned 14 Months Early About the Coldcard Flaw","type":"news_article","url":"https://phemex.com/academy/coldcard-security-flaw-warning"},{"credibility":2,"name":"Cryptopolitan — Coinkite CTO Peter Gray linked to the code behind the $114M Coldcard hack","type":"news_article","url":"https://www.cryptopolitan.com/coinkite-cto-peter-gray-linked-coldcard-hack/"},{"credibility":2,"name":"Bitcoin Magazine — Coinkite Releases Fixed Firmware After Coldcard Bug","type":"news_article","url":"https://bitcoinmagazine.com/business/coinkite-releases-fixed-firmware-after-coldcard-bug-ai-likely-involved-in-the-hack"},{"credibility":2,"name":"Bitcoin Magazine — The Coldcard Hacker Left A Paper Trail That May Already Be In Law Enforcement Hands","type":"news_article","url":"https://bitcoinmagazine.com/technical/hunting-down-the-coldcard-hacker-wave-1-thief-may-be-known-to-fbi"},{"credibility":2,"name":"CryptoTimes — Coldcard Hacker Swaps Bitcoin to ETH via THORChain and Tornado Cash","type":"news_article","url":"https://www.cryptotimes.io/2026/08/05/coldcard-hacker-swaps-bitcoin-to-eth-via-thorchain-and-tornado-cash/"},{"credibility":2,"name":"Crystal Intelligence — Tracing the Coldcard hack: where the stolen Bitcoin went","type":"on_chain","url":"https://crystalintelligence.com/investigations/coldcard-exploit-tracing-stolen-bitcoin/"},{"credibility":2,"name":"Cryptopolitan — Coldcard overhauls data retention policy, prepares for legal obligations","type":"news_article","url":"https://www.cryptopolitan.com/coldcard-overhauls-data-retention-policy/"},{"credibility":2,"name":"WeirFoulds — The Coldcard Exploit: Why Victims May Have Two Routes to Recovery","type":"other","url":"https://www.weirfoulds.com/the-coldcard-exploit-why-victims-may-have-two-routes-to-recovery"},{"credibility":2,"name":"Bitcoin.com News — Coinkite Faces Class Action Threat","type":"news_article","url":"https://news.bitcoin.com/regulation-and-legal/coinkite-faces-class-action-threat-as-bitcoin-wallet-bug-costs-users-over-1300-btc/"},{"credibility":2,"name":"Crowdfund Insider — Coldcard Issues Enhanced Firmware Update","type":"news_article","url":"https://www.crowdfundinsider.com/2026/08/300062-coldcard-issues-enhanced-firmware-update-amid-ongoing-bitcoin-btc-theft-fallout/"},{"credibility":2,"name":"Halborn — Explained: The Coldcard Hack (July 2026)","type":"research","url":"https://www.halborn.com/blog/post/explained-the-coldcard-hack-july-2026"},{"credibility":2,"name":"SlowMist — Coldcard $111 Million Theft: A Deep Dive into the Private Key Vulnerability","type":"research","url":"https://slowmist.medium.com/coldcard-111-million-theft-a-deep-dive-into-the-private-key-vulnerability-8e51d1a969d3"},{"credibility":2,"name":"BingX — Coldcard exploit triggers 210,000 BTC shift by long-term holders","type":"news_article","url":"https://bingx.com/en/flash-news/post/coldcard-hack-linked-to-m-theft-as-long-term-holders-move-btc-glassnode-says"}],"summary":"Coldcard is a Bitcoin-only hardware wallet produced by Toronto-based Coinkite Inc. Beginning July 30, 2026, attackers exploited a firmware build error introduced in March 2021 that caused seed generation to fall back on a weak software pseudorandom number generator instead of the device's hardware entropy source, reducing effective key strength to as little as 40 bits on older models. Across four attack waves spanning several days, roughly 1,816 BTC (approximately $116 million) was drained from over 5,200 addresses without any physical access to the affected devices, making it the largest hardware wallet exploit on record.","timeline":[{"date":"2021-01-28","event":"Vulnerable macro check exists in the libngu library, predating its integration into Coldcard firmware.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"date":"2021-03-01","event":"Coldcard firmware migrates to the libngu cryptographic library, introducing the vulnerable code path.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"date":"2021-03-17","event":"Firmware version 4.0.0 released with the RNG fallback bug active; seed generation silently begins using weak Yasmarang PRNG on Mk2/Mk3 devices.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"date":"2022-03-11","event":"A 32-bit reseed API is added to libngu.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"date":"2022-03-14","event":"Mk4 firmware v5.0.0 released including 32-bit reseed; Mk4/Q/Mk5 seeds carry ~72-bit effective entropy rather than 40 bits, but remain below the intended 128-bit security level.","source":"Block Engineering Blog","source_url":"https://engineering.block.xyz/blog/predictable-rng-fallback-and-32-bit-reseed-in-coldcard-firmware"},{"date":"2025-05-01","event":"Bitcoin developer James O'Beirne reportedly flags the flawed randomness code to Coinkite. According to third-party reporting, CTO Peter Gray responds with an argument from absence rather than a technical review.","source":"Phemex — Coinkite Was Warned 14 Months Early About the Coldcard Flaw","source_url":"https://phemex.com/academy/coldcard-security-flaw-warning"},{"date":"2026-07-30","event":"Wave 1 attack: approximately 1,082.65 BTC drained from ~1,196 addresses in approximately 41 minutes. Coinkite issues a security advisory the same day.","source":"TRM Labs","source_url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"},{"date":"2026-07-31","event":"Wave 2 attack: ~594 BTC drained from ~500 addresses in ~25 minutes. Coinkite CEO Rodolfo Novak publishes public apology. Emergency patched firmware released for all models.","source":"CoinDesk / TRM Labs","source_url":"https://www.coindesk.com/tech/2026/07/31/major-bitcoin-wallet-flaw-drains-594-btc-in-25-minute-sweep"},{"date":"2026-08-01","event":"Wave 3: approximately 208 BTC drained from ~1,912 addresses.","source":"Fortune","source_url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/"},{"date":"2026-08-03","event":"Wave 4 detected; cumulative total reaches approximately 1,816 BTC (~$116 million) from over 5,200 addresses.","source":"Fortune / TRM Labs","source_url":"https://fortune.com/2026/08/03/bitcoin-owners-116-million-hack-coldcard-coinkite-exploit/"},{"date":"2026-08-04","event":"Limited laundering activity detected: 64.9 BTC deposited to Wasabi Wallet; 200 ETH deposited to Tornado Cash after BTC converted via THORChain.","source":"CryptoTimes","source_url":"https://www.cryptotimes.io/2026/08/05/coldcard-hacker-swaps-bitcoin-to-eth-via-thorchain-and-tornado-cash/"},{"date":"2026-08-04","event":"Coinkite reverses policy of automatically deleting customer records, citing anticipated legal obligations from the incident.","source":"Cryptopolitan","source_url":"https://www.cryptopolitan.com/coldcard-overhauls-data-retention-policy/"},{"date":"2026-08-07","event":"Roughly 90% of stolen BTC remains unmoved; ~600 flagged attacker addresses shared with exchanges and law enforcement. No arrest or fund seizure announced.","source":"TRM Labs","source_url":"https://www.trmlabs.com/resources/blog/the-largest-hardware-wallet-exploit-of-2026-inside-the-usd-116-million-coldcard-hack"},{"date":"2026-08-01","event":"Coinkite releases hardened follow-up firmware (v5.6.1 for Mk4/Mk5, v1.5.1Q for Q) approximately three weeks after initial emergency patch, following a comprehensive post-incident audit.","source":"Crowdfund Insider","source_url":"https://www.crowdfundinsider.com/2026/08/300062-coldcard-issues-enhanced-firmware-update-amid-ongoing-bitcoin-btc-theft-fallout/"}]},"v":1}