What happened
On May 18, 2021, Venus Protocol's BNB Smart Chain money market suffered a large XVS-collateral liquidation event. During a sharp rise in XVS, a major account supplied XVS and borrowed BTC and ETH; when the price reversed, the position and other accounts became undercollateralized. Venus reported about $77 million of protocol loss.
Other reports measure more than $100 million of bad debt or over $200 million of liquidations, which are different metrics and are not combined here.
Collateral parameters and oracle risk controls did not contain an extreme XVS price move. Once collateral was valued at the elevated price, debt could outpace realizable collateral after reversal. Lending markets must test collateral concentration, adverse price moves, oracle-deviation and circuit-breaker behavior, and liquidation depth, not only code-level authorization and arithmetic paths.
Case & protocol details
Attack Timeline
Venus allowed volatile XVS collateral to support BTC and ETH borrowing without price-deviation controls adequate for the extreme market move. At the elevated XVS price, accounts could borrow against collateral whose realizable value collapsed when the price reversed. Liquidation sales intensified the decline, and collateral no longer covered outstanding BTC and ETH debt.
Venus's postmortem said it did not identify a group that stole protocol funds; it characterized the event as an economic and risk-management failure rather than a contract-code exploit.
Evidence & learning
Attack pattern
Compare incidents →Sources and on-chain records
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