Moonwell Loses $8.7 Million as Bitcoin (BTC) Borrowed in Base Exploit

Direct Transfers Bypassed the Supply Cap

Lending protocol Moonwell lost approximately $8.7 million on Base on Thursday, and the on-chain trail shows the attacker never had to defeat the protocol's supply limit at all. Security researchers CertiK and Blockaid attributed the drain to price manipulation of MAMO, a thinly traded token Moonwell accepted as collateral — the low-liquidity class that also includes memecoins like Shiba Inu and dogwifhat — while PeckShield independently pegged the loss at $8.7 million. As of early Friday, the proceeds sat in a single Ethereum address holding roughly 8.73 million DAI. The loophole is structural. Moonwell caps how much MAMO can be supplied through its normal deposit route, and that limit is enforced only when a depositor mints shares. At 09:12:59 UTC the attacker made one legitimate deposit of 7.1 million MAMO, receiving 346 million shares — then stopped depositing. On-chain records show that at 09:19:59 UTC they pushed 34,910,397 MAMO straight to the market contract, and 70 seconds later another 18,482,894, about 53 million tokens in total. Neither transfer minted a single share; each burned an identical 120,017 gas and emitted only an interest-accrual event and a token transfer. Because Moonwell runs on Compound v2 code, a share is valued as pool holdings divided by shares outstanding, so a direct transfer inflates every existing share at once. The market's exchange rate moved from 0.0205 to 0.0755 — roughly 3.7x higher — letting the attacker's 346 million shares claim about 26 million MAMO. Against that inflated collateral they borrowed cbBTC, the Coinbase-wrapped bitcoin, alongside USDC and wstETH.

KLA Insiders Sold $64 Million Into the Slide

The exploit landed in the same week that a TradFi disclosure gap drew scrutiny. AI chip-equipment maker KLA Corporation has fallen 40% since June 30, erasing roughly $160 billion of market value as the stock slid from an all-time high of $307.37 to a $183.77 close — capitalization dropping from $401 billion to $240 billion. Over the same window, SEC filings disclosed more than $64 million of insider sales. President Richard Wallace led with $17.4 million; CFO Bren Higgins sold $13.9 million; Executive Vice President Brian Lorig and Officer Mary Beth Wilkinson each crossed $12 million; Semiconductor Products President Ahmad Khan sold $6.6 million; Senior Vice President Virendra Kirloskar sold $1.8 million. Each sale occurred on its own date and price, spread across the decline rather than clustered after it — and no insider made a single open-market purchase in that stretch. The company says most sales followed regularly scheduled compensation plans, and the vast majority carried a Rule 10b5-1 representation, the advance-programmed trading plan that serves as a defense against insider-trading liability under SEC rules on selective disclosure. Planned selling is not proof of a bearish forecast, and absent buying is not proof of overvaluation — but $64 million out and $0 in is an uncomfortable asymmetry for anyone who chased the summer AI rally: $10,000 invested at the June 30 peak is now worth under $6,000. The latest Form 4 reached EDGAR on August 14 for an August 13 sale, and filings are due within two business days, so later August trades may not yet be on record. Across the semiconductor complex, from equipment vendors to designers such as Arm Holdings, the drawdown is testing how much of the AI premium survives. Readers tracking the market in real time can follow live spot and futures prices on Gate.

Borrow Caps Frozen, Safeguards Still Unbuilt

The common thread is that guardrails arrived only after the damage. Moonwell said in an official post that borrow caps across all Core Markets on Base were set to 1 wei, freezing new borrowing and limiting further impact; the root cause, verifiable in the transaction sequence above, was a supply-cap check tied exclusively to share minting. On-chain data shows total value locked fell from about $73 million before the attack to roughly $45 million by early Friday — a sum several times the approximately $1.9 million in protocol revenue recorded over the past year. A June contributor proposal for an automatic circuit breaker on oracle price deviations drew three replies and no vote. Until cap enforcement covers direct transfers, share-inflation attacks remain an open door.