Alephium Bridge Loses $815K in Offchain Exploit Amid Bridge Hack Spree

- Hackers mint 13.76 million wrapped ALPH tokens through forged offchain approvals, draining $815,000 on Ethereum and BNB Chain - Alephium urges all liquidity providers to withdraw funds immediately as May 2026 sees surge in bridge exploits across DeFi On May 31, 2026 (UTC), Cryptopolitan reported that hackers exploited the Alephium Token Bridge on Ethereum and drained approximately $815,000 by minting 13.76 million wrapped ALPH tokens through forged offchain transactions. The breach affected both Ethereum and BNB Chain bridge contracts, and it prompted Alephium to issue an urgent warning for liquidity providers to withdraw from all ALPH pools immediately to prevent further losses. The incident highlights ongoing vulnerabilities in cross-chain bridge infrastructure, and it stands out from other recent bridge hacks because the attackers specifically targeted backend offchain verification logic rather than compromising private keys. According to Alephium’s official statement on May 31, 2026, and supporting on-chain analysis, the exploit stemmed from a flaw in the bridge’s offchain backend logic. The attacker submitted counterfeit Verified Action Approvals (VAAs), which the backend erroneously accepted as valid, thereby allowing the unauthorized minting of 13.76 million wrapped ALPH tokens on Ethereum—far exceeding the existing token supply—without any legitimate cross-chain deposits or guardian approval. As a result of the forged minting, the attack enabled the theft of 200,967 USDT, 17,594 USDC, 5.18 WETH, and 0.335 WBTC on Ethereum, while it also enabled the theft of 36,750 USDT and 24.386 WBNB on BNB Chain. Security firm Blockaid detected the incident, and the entire sequence—from the forged token minting to laundering proceeds via Tornado Cash—played out in roughly seven minutes, according to blockchain analyst Specter. A technical review by Alephium’s team found that the offchain verification layer lacked robust authentication for validation messages, and this weakness enabled the bridge to accept forged VAAs without sufficient signature and approval checks. In addition, analysts noted that, unlike the Gravity Bridge and Verus-Ethereum Bridge exploits earlier in May, which involved key compromise or direct contract bypass, the Alephium incident did not involve leaked private keys or manipulation of validator sets. In response to the breach, Alephium halted its Token Bridge services and instructed all liquidity providers on Uniswap, PancakeSwap, and other decentralized exchanges to promptly withdraw their ALPH positions. The team cautioned that continued trading could enable attackers to further offload stolen assets and amplify user losses, and it warned that liquidity remaining in pools could be at heightened risk as the exploiters attempt to exit positions. Industry analysts note that the Alephium hack marks the third major bridge exploit in May 2026 and contributes to over $17 million stolen from multiple protocols as bridges remain a prime target in DeFi. DefiLlama data estimates that total bridge-related crypto hacks in 2026 now approach $326 million, while bridge exploits make up $3.2 billion of the $16.6 billion lost to hacks sector-wide to date. The Alephium Token Bridge attack exposed a critical vulnerability in the backend offchain verification logic because the system accepted forged messages and enabled mass unauthorized token minting without any compromise of guardian keys. This breach highlights persistent security challenges in bridge infrastructure, especially at the offchain verification layer, and it emphasizes the urgent need for comprehensive reviews of all bridge system components. As of 02:08 UTC on May 31, 2026, market data shows that Solana (SOL) is trading at $82.992 with a 0.167% increase, Tether USDt (USDT) is trading at $0.998 with a -0.021% change, and BNB (BNB) is trading at $727.525 with an 11.009% increase. Meanwhile, Uniswap (UNI) is trading at $3.052 with a -0.644% change, PancakeSwap (CAKE) is trading at $1.497 with an 8.39% increase, and USDC (USDC) is trading at $1 with a -0.005% change.