Allbridge Core just lost $1.65 million to a flash loan attack. Again. The same pool-ratio manipulation vector that bled it in April 2023. Same chain. Same playbook. Different date. This is not a new vulnerability. It is a willful refusal to fix a critical architectural flaw.
I spent 2017 verifying Zilliqa’s Nakamoto Consensus implementation against their whitepaper. I found shard collision edge cases the team missed. That 12,000-word breakdown taught me one thing: if a protocol promises scalability without cryptographic proof, it is hiding risk. Allbridge promised interoperability without oracle anchoring. It hid risk behind a simple AMM equation.
Context: The Bridge That Refused to Learn
Allbridge Core operates as a cross-chain stablecoin bridge connecting Solana to Ethereum Virtual Machine chains—BSC, Ethereum, Polygon. It uses a pooled AMM model: liquidity providers deposit USDC or USDT into pools, and users swap between chains through atomic swaps. The exchange rate is determined by the ratio of stablecoins in each pool. No external oracle. No slippage protection beyond what the AMM's curve provides.
On March 2025, an attacker borrowed a flash loan from Kamino Finance on Solana, executed a series of swaps that manipulated the pool ratio, and extracted $1.65 million in stablecoins. The funds were then bridged to Ethereum and sent to Tornado Cash. The team paused the protocol and issued a public plea for the attacker to return stolen funds—a gesture that has historically yielded near-zero recovery.
This exact attack pattern was used against Allbridge in April 2023 on BNB Chain. The modus operandi is identical: flash loan, pool ratio manipulation, withdrawal of arbitrage profit. Two years later, the codebase still lacks the most basic countermeasures.
Core: Dissecting the Pricing Logic Failure
Let me be precise. Audit the code, not the pitch. Allbridge’s vulnerability is not in its cross-chain messaging layer. It is in the pricing engine. The protocol uses a constant product formula where the exchange rate between two stablecoins in a pool is purely a function of their relative reserves. An attacker can temporarily swamp one side of the pool with a flash loan, causing the rate to deviate far from the real-world stablecoin peg. They then swap the other stablecoin at inflated price, drain the excess, and repay the flash loan. The pool ends up imbalanced, but the profit is gone.
Trust no one, verify everything. If Allbridge had integrated a Chainlink price feed for stablecoin pegs, the oracle would have rejected any trade that deviated more than 0.5% from the market price. It did not. If it had enforced a slippage check—minimum output amount—the flash loan arbitrage would have failed. It did not. If it had a time-weighted average price (TWAP) oracle, manipulators would have needed extended block-by-block attacks. It had nothing.
Complexity hides risk. Some argue that Allbridge’s simplicity—no validators, no relayers, just pools—makes it safer. It does not. Simplicity in operations can mask fragility in design. A simple AMM with no external pricing is a ticking bomb in a high-leverage environment. The 2023 attack was the first detonation. The 2025 attack proves the fuse was never removed.
Based on my MakerDAO collateral audit in 2020, where I identified a potential oracle manipulation vector in Chainlink-KNC integration, I know that even sophisticated protocols underestimate the sensitivity of AMM pricing to flash loans. Maker adjusted its threshold after my report. Allbridge did not adjust anything.
Contrarian: What the Bulls Got Right
To be fair, the team responded quickly. Within minutes of the attack, they paused the protocol, preventing further drains. They publicly identified the compromised pools and asked liquidity providers to withdraw. They also reached out to the attacker via on-chain messages, offering a bug bounty for return of funds. This shows operational awareness.
Moreover, the Allbridge multichain thesis remains valid: bridging Solana assets to EVM chains is a genuine use case. Solana’s DeFi ecosystem needs efficient cross-chain stablecoin movement. The incident does not invalidate that need. It only invalidates Allbridge’s current implementation.
The bulls might also point out that $1.65 million is small relative to the total value secured by major bridges. Stargate has $15 billion. Synapse $3 billion. Allbridge’s TVL was likely under $50 million. The absolute loss is contained. But the reputational loss is exponential.
Takeaway: A Bridge to Nowhere
Allbridge has two choices: either completely rebuild its pricing mechanism with external oracles, slippage protections, and a formal verification audit from a top-tier firm like Trail of Bits, or watch its TVL evaporate to zero. The 2023 incident was a warning shot. The 2025 incident is the headshot. No liquidity provider in their right mind will return until the codebase is rewritten from scratch.
This case also sends a systemic signal: the market should accelerate toward native cross-chain protocols like Circle’s Cross-Chain Transfer Protocol (CCTP) or IBC-based bridges that eliminate AMM-based pricing entirely. Until then, every flash loan is a potential landmine.
