Developer Recovers $2 Million Locked in 2016 ICO Contract for Nine Years Through Whitehat Exploit

Jun 1, 2026

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.