Developer Florent recovered approximately 1,003 ETH worth roughly $2 million that had been trapped in a 2016 HongCoin ICO contract for nine years using a whitehat exploit posted June 1, 2026. The contract was meant to auto-refund investors after the sale fell short, but a bug left funds stuck. 48 original investors can now claim the unfrozen funds, with two already reclaiming 96.5 ETH and voluntarily rewarding Florent.
HongCoin ICO recovery
- ▪The HongCoin sale fell short of its goal and was meant to auto-refund investors' ETH, but a bug left the money stuck
- ▪Two HongCoin investors have reclaimed a combined 96.5 ETH, approximately $193,000, and voluntarily sent Florent a whitehat reward
- ▪The article was published on June 1, 2026
- ▪A developer known as Florent helped recover approximately 1,003 ETH, worth roughly $2 million at current prices, that had been trapped in a 2016 HongCoin initial coin offering contract for nine years
- ▪The HongCoin contract belongs to an Ethereum token sale from 2016 that was pitched as a community-run investment fund
- ▪48 original HongCoin investors can now claim the unfrozen funds, with 41 needing the balance reset and seven holding small enough amounts to refund directly
Smart contract vulnerability
- ▪Calling the HongCoin team's admin function with a very specific input value would reset a holder's balance back to 1 due to missing overflow protection, allowing the refund check to pass and the ETH to be released
- ▪Years of partial refunds in the HongCoin contract had dragged the global counter down to 356, capping total refunds at 3.56 ETH, approximately $7,000, while most remaining holders held far more
- ▪The HongCoin refund function rejected any holder whose token balance was larger than a global counter
- ▪The HongCoin contract was deployed with an old version of the Solidity programming language and did not have protections against overflowing errors, a vulnerability that was patched later with the SafeMath library
Whitehat recovery process
- ▪Florent used Claude Code to accelerate the work in sorting and clustering contracts but found the model has flaws when analyzing smart contracts themselves
- ▪The HongCoin admin function was restricted to HongCoin's multisig, so Florent emailed the team, validated the sequence on a Foundry mainnet fork, and the team signed the unlock transactions itself
- ▪Florent set up a self-hosted Ethereum node and built a scanner to flag every contract holding more than 100 ETH
- ▪The HongCoin team signed 41 transactions, one per blocked holder, covering the roughly 1,000 ETH that was truly stuck
- ▪The HongCoin recovery process took about a week from Florent's first email to the team
- ▪Florent posted an X thread about the HongCoin recovery early on June 1, 2026
Additional contract recoveries
- ▪On May 24, 2026, Florent described freeing 19.329 ETH, about $40,590, from two older contracts
- ▪Florent recovered 14.190 ETH from a Liquality Wallet user's seven expired atomic swaps and refunded the funds on the user's behalf after Liquality wound down its app in 2024
- ▪Florent recovered 5.141 ETH from a failed January 2018 ICO that had the funds behind an uncalled public refund function
DeFi security landscape
- ▪DeFi attacks totaled hundreds of millions of dollars across April 2026 alone, led by a roughly $293 million drain at Kelp DAO
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