A vulnerability in the Moonwell protocol on the L2 Base network was exploited by an unknown attacker, leading to the theft of assets valued at approximately $8.7 million. The incident was highlighted by researchers at CertiK.
— CertiK Alert (@CertiKAlert) August 27, 2026
The assailant reportedly manipulated a low-liquidity collateral of the MAMO token and borrowed cbBTC, USDC, wstETH, and ETH against it, leaving the protocol with unsecured debt.
According to Coinminutes, the estimates of the losses vary and are likely to rise further.
Initial on-chain evaluations indicated losses of around 50.6 cbBTC, or more than $4 million. Analysts from ExVul assessed the damage at approximately 71.36 cbBTC (around $5.7 million), while CertiK reported it at $8.7 million, and several other observers estimated it to be close to $9 million.
Moonwell representatives confirmed the incident, linking it to the main MAMO market. Developers restricted lending on the Base network to a mere 1 wei to prevent further debt accumulation.
We are aware of an issue affecting the MAMO Core Market on Base and are actively investigating.
As a precaution, borrow caps for all Core Markets on Base have been set to 1 wei, preventing new borrowing and limiting the potential for further impact. The supply caps for MAMO and…
— Moonwell (@MoonwellDeFi) August 27, 2026
Additionally, supply limits have been imposed on the MAMO and WELL tokens.
In the hours following the attack, MAMO experienced a spike in trading volume, likely due to artificial inflation, but subsequently fell in price without a significant crash.
Source: CoinGecko.The native WELL token saw a correction of 13%, dropping to $0.0032.
Source: CoinGecko.It’s worth noting that on August 19, developers of the Maya Protocol halted operations following a hack that resulted in losses of approximately $1.7 million.