Allbridge Halts Core Bridge After $1.65M Flash Loan Exploit

Cross-chain protocol Allbridge paused its Core bridge on July 20 after an attacker drained roughly $1.65 million from its Solana liquidity pools, according to blockchain security firms PeckShield and CertiK.

"Allbridge Core is experiencing a security incident, and the protocol has been paused as a precaution," the team said, warning liquidity providers: "If you have liquidity in affected pools, please withdraw now."

Allbridge Core moves native stablecoins such as USDC and USDT across chains using liquidity pools, rather than issuing wrapped tokens. The attacker took out a $1.12 million flash loan — a loan borrowed and repaid within a single transaction — from Solana lending protocol Kamino, then rapidly swapped USDC and USDT to distort the pools' internal ratios before withdrawing assets at favorable rates, on-chain analyst Onchain Lens reported.

The stolen funds were bridged to an Ethereum address and dispersed across additional wallets. Allbridge said the manipulation left its pools imbalanced, creating a temporary arbitrage window, and asked traders who profited from the distortion to return funds to compensate affected liquidity providers.

A Repeat of 2023

The incident echoes a flash loan attack in 2023 that drained roughly $650,000 from Allbridge's BNB Chain pools. In its postmortem at the time, Allbridge committed to deploying a single liquidity pool per chain, an architecture intended to make same-transaction flash loan manipulation structurally impossible.

The July exploit targeted a USDC and USDT pool operating side by side on Solana — the multi-stablecoin configuration the earlier fix was meant to eliminate. Allbridge said it recovered most of the funds after the 2023 incident.

The protocol has not published a final accounting of how much of the $1.65 million remains under the attacker's control or laid out a timeline for resuming operations.