Moonwell hit by $9M attack, fourth incident in a year

Nearly $9 million in deposits has been drained from the Moonwell DeFi lending platform on Base by an attacker.

About an hour after the attack began, blockchain security firm Blockaid raised the alarm.

Moonwell later confirmed the incident, telling users that borrow caps and supply caps for MAMO and WELL had been reduced to one wei, “preventing new borrowing and limiting the potential for further impact.”

Blockaid’s Exploit Detection identified suspicious activity against @MoonwellDeFi on Base.
An attacker manipulated MAMO collateral pricing to borrow cbBTC from the mCBTC market.
Observed impact so far: 50.6 cbBTC ($4.0M+) drained
More details to follow.

— Blockaid (@blockaid_) August 27, 2026

This price manipulation worked by artificially raising the price of MAMO, a token with low liquidity used as collateral on Moonwell, and then borrowing against it.

According to reports, the attacker spent $7 million to pump MAMO's price, then sold it for an estimated loss of $3.8 million.

The stolen assets include cbBTC, USDC, WETH, and wstETH.

Although Blockaid's initial alert estimated the damage at over $4 million, the losses grew. The attacker exchanged the stolen funds for the non-freezable stablecoin DAI, with 8.7 million of it now in their Ethereum address that was funded via Tornado Cash.

Moonwell's fourth pricing-related incident in a year

This loss is the fourth incident for Moonwell in under a year, all involving pricing issues.

During the market crash on October 10, a price discrepancy caused $12 million in liquidations and $1.7 million in bad debt.

The next month, the Balancer hack's aftermath created problems with the wrsETH/ETH oracle, leading to $3.7 million in bad debt.

In February, a “vibe-coded” Moonwell contract priced cbETH at $1.12 (instead of 1.12 ETH) when its actual worth was about $2,200.

That mistake caused abrupt liquidations of positions backed by cbETH and left the market with $1.8 million in bad debt.