RedSonic Vault Exploit Drains 9.25 ETH in Ethereum Flash Loan Attack
Ethereum (ETH)
Editor:
Eugene Serbin
bitcoinethereumnews.com reports that RedSonic Vault lost 9.25 ETH to a flash loan attack executed in a single transaction. Blockchain security firm ExVulSec identified the exploit, which manipulated a permissionless asset-registration function to double-count collateral. The attacker flash-loaned 1,139 WETH from Balancer to fund the operation without using any upfront capital.
By registering stETH as a second asset, the attacker created a class called rsvstETH that shared the same underlying stETH balance as rsvETH. This design allowed the attacker to inflate the vault's share price artificially without minting new shares. After depositing 1,130 ETH to acquire nearly 99% of outstanding rsvETH shares, the attacker deposited 9.34 stETH directly into the vault.
This single deposit pushed the share price higher, instantly increasing the value of the attacker's existing holdings. The attacker then redeemed rsvETH for 1,139.5 ETH, securing a 9.25 ETH profit from the price inflation. A separate redemption of rsvstETH shares for stETH allowed the same underlying collateral to pay out twice. The exploit contract self-destructed after execution, which security researchers note can complicate on-chain tracing efforts.
How the market reacted
Whalio's own Binance spot order flow for ETH, measured when this story was written up on 6 September 2026. Not the outlet's figures.
ETH is trading at $2,480.34 with a 1-hour buy ratio of 54.6% and a 4-hour buy ratio of 54.0%. These short-term figures indicate stronger buying pressure compared to the 24-hour buy ratio of 51.8%, suggesting that aggressive accumulation is currently outpacing selling. Volume delta data reinforces this trend, showing a positive flow of +$1,465,776 in the last hour and +$8,950,471 over four hours. This means buyers are actively absorbing sell orders, pushing the net volume higher in the immediate term. The cumulative volume delta for the 24-hour period stands at +$20,930,133, confirming that net buying has been the dominant force throughout the day.
The latest daily buy ratio of 46.8% sits at the 16th percentile of the last 322 days, against a median of 49.5% - weaker buying than most days.
Was that an ordinary day?
The same Binance spot measurements for ETH, averaged over the days leading up to the story.
Over the preceding week, the 7-day average buy ratio was 50.8%, making today's 24-hour reading of 51.8% a slight increase of 0.9 points. However, spot volume has been subdued, measuring at only 0.47 times the weekly average. While net buying has occurred on three of the past seven days, the total volume delta for the eight-day period was +$94,475,283. This indicates that while the directional bias remains mildly positive, the actual trading activity is significantly lower than usual. The price has risen by just 0.9% over the eight-day window, reflecting this cautious market participation.