Two mining pools largely control the Ravencoin mining, and have already begun rolling back the blockchain to a point prior to the invalid blocks. This is a controversial move in the crypto world, where immutability is considered sacrosanct. It's also disruptive, because legitimate transactions during that time period will be undone, with coins returned to the origin wallets. Several exchanges have halted RVN withdrawals and deposits, anticipating potential issues.
Ravencoin rolls back blockchain after exploit
Attackers exploited a vulnerability in Ravencoin, a blockchain based on the bitcoin codebase, to mine invalid blocks. Although Ravencoin subsequently patched the bug, the blockchain contains roughly four days of invalid history.
Harmony token plunges 40% after unauthorized mint
An attacker was able to exploit the Harmony blockchain to mint 4 billion of the network's $ONE token. The massive increase in token supply caused the token price to plunge 40%.
Harmony paused its token bridge and asked exchanges to freeze tokens coming from four addresses connected to the attacker. They also said they were considering a possible rollback — that is, reverting the blockchain to a pre-attack state, undoing all transactions since that point. This is a very controversial choice in the crypto world, where blockchains are prized for their immutability. It also becomes less effective if attackers are able to move tokens off the network before the rollback happens.
This is the second time Harmony has had mint-related issues. In January 2024, a bug caused around 150 million $ONE to erroneously be minted and distributed to 79 wallets. And in June 2022, Harmony suffered a $100 million theft, later attributed by the US FBI to North Korean hacking groups.
Coinsbuy exploited for $8 milllion
The Coinsbuy crypto platform was exploited for around $8 million across both the Ethereum and Tron blockchains. The attacker was able to steal the funds from eight wallets belonging to the exchange. The wallets were later replenished by Coinsbuy, suggesting that the attack vector did not involve compromising the wallets themselves.
Coinsbuy has said that the vulnerability has been addressed, and offered a $100,000 "bounty" for the returned funds.
Step App "move-to-earn" project shuts down
Step App, one of the last surviving "move-to-earn" projects from the 2022 crypto fitness fad, announced it will shut down all services on August 21. The project advertised itself as a "fitness app that pays you", and was essentially a step counter that paid crypto rewards. Users had to first buy the Step App's FITFI token to purchase an NFT representing sneakers, then were rewarded with the project's KCAL tokens for each minute they spent moving — although the number of minutes that would generate rewards were capped, often at just a few minutes, and required more NFTs to increase.
Holders of the project's FITFI and KCAL tokens have two weeks to cash out, although they're not likely to recoup much. FITFI trades at fractions of a cent, and KCAL trades at $0.01 — far below its $1–$4 prices from the project's peak in 2022 and 2023. Holders of Step NFTs are likely similarly out of luck.
Proof of Attendance Protocol (POAP) shuts down
Proof of Attendance Protocol, or POAP, was a darling of the web3 hype cycle and supposed proof of the utility of NFTs. "Using blockchain technology, POAP tokenizes your memories, so they can last forever and be truly yours," the website gushes, presenting a solution to a problem I previously did not realize I had.
The tokens were typically issued as souvenirs from crypto conferences or other events, and were supposed to function as cryptographically verifiable proof that the owner attended an event. The fact that the POAPs were tradable of course undermined this somewhat, but nevertheless the crypto world had come up a number of reasons why POAPs would be the future of event planning and digital identity and all kinds of things.
Now, the project's co-founder has announced that "Unfortunately, crypto's funding cycles and distribution dynamics made it hard to build a sustainable company without cannibalizing the ethos that made POAP mean something. Building on a fragile and quickly evolving stack, in the middle of an incredible hype cycle, only added to the challenges."
Coldcard hardware wallet flaw sees more than 2,000 BTC (~$130 million) drained across thousands of wallets
Thousands of users of a hardware wallet called Coldcard, a physical device developed by the Canadian Coinkite firm to allow bitcoin holders to store their bitcoin on a device that's not connected to the internet, have suffered at least 2,055 BTC (~$130 million) in combined losses after thieves began exploiting a flaw with the wallet firmware's seed phrase generation. A 2021 version of the device firmware, which affects a wide range of Coldcard devices, skipped the device's more secure hardware randomness generator and instead fell back to generating seed phrases with random numbers seeded from the device's serial number and clock registers. The resulting seed phrases are relatively trivially guessed, and hackers have been methodically draining vulnerable wallets as researchers warn that all vulnerable Coldcard devices will be drained soon if their owners do not move assets to secure wallets.
An estimated 2,055 BTC (~$130 million) and counting has been drained in the days following the discovery of the attack, which began with an attack that saw 594 BTC ($38 million) drained from about 500 separate wallets. The first attack seemed to intentionally target higher-value wallets, with only wallets containing 0.15 BTC (~$9,500) or more impacted. Attacks have come from an estimated 15 unique groups, according to Galaxy Research.
Hardware wallets are often used by more security conscious users, or those with more significant sums of money at risk, because the lack of internet connection makes the devices less vulnerable to phishing or malware-based attacks. However, if a wallet seed phrase can be obtained by an attacker, the lack of internet connection is no barrier to theft. Coldcard describes itself as "ultra-secure", and its website is filled with reviews describing the product as "one of the most secure Bitcoin hardware wallets ever built".
Two arrested after Flare Network staking site scammed users out of 3.4 million XRP (~$8.5 million)
South Korean police say scammers running a fake staking website under the name of the real Flare Network took 3.4 million XRP (~$8.5 million) from 71 investors. It's possible the scammers stole closer to $19 million. Victims were promised guaranteed returns of 1.5% to 1.8% a month; the site was only live for about a week in October 2025 before the operators disappeared with the deposits.
Two men were arrested on fraud charges, and Korean police are seeking a third. They reportedly advertised the scam project via YouTube and online articles.
- "12.3 Billion Won Crypto Scam Group Arrested", The Chosun
Triple-A hacked for $11.8 million
Singapore-based stablecoin payments company Triple-A confirmed that an attacker stole $11.8 million in company funds from its treasury wallets. The company briefly took some services offline while they investigated the hack.
Triple-A did not say how much was taken or how the wallets were compromised, and said the impact was limited to "specific operational accounts" and able to be covered by treasury reserves. Blockchain analyst Specter estimated the loss at $11.8 million, stolen across the bitcoin and Tron networks.
Poolin bitcoin mining pool operator files for bankruptcy
Poolin Technology, once among the largest bitcoin mining pools in the world, has filed for bankruptcy, listing more than $100 million in debts against less than $10 million in assets.
The largest liability by far is the $163.7 million owed to roughly 11,700 people who had money in Poolin Wallet when the company froze withdrawals in September 2022, citing "some liquidity issues" during that year's crash. Instead of returning their bitcoin, Poolin handed them IOU tokens, which it never redeemed.
Poolin was founded in Beijing in 2017 and in better days accounted for almost a fifth of the bitcoin network's hashrate.
- Chapter 11 voluntary petition filed by Poolin Technology
- "Poolin, Once One of Bitcoin's Biggest Mining Pools, Files for Bankruptcy", Decrypt [archive]
42DAO's Balance Coin algorithmic stablecoin crashes after $912,000 theft
Balance Coin, a small algorithmic stablecoin built on BNB Chain, lost its dollar peg and crashed to fractions of a cent after an attacker successfully exploited a flaw in its pricing logic. The attacker was able to trick the system into accepting an incorrectly low bitcoin price, which they then used to drain multiple vaults used by the project's lending protocol.
The attacker ultimately profited by about $912,000, consisting of funds stolen from 42DAO, the entity that runs the Balance protocol.
Wanchain bridge on Cardano exploited for more than $9 million
An attacker exploited the Wanchain bridge, stealing 515 million NIGHT tokens that had been bridged from Cardano to BNB. The NIGHT token belongs to Midnight, a privacy-focused blockchain linked to Cardano. The stolen tokens were priced at $9 million to $10 million at the time of the theft, although the massive outflow of tokens briefly caused the NIGHT token price to drop by about 43%.