SlowMist Cosine: The fundamental reason for the Balancer hack is that the calculation error in the scaling factor of Balancer v2's Composable Stable Pool implementation can be exploited for profit through low-liquidity swaps.

Jinse Finance reported that SlowMist's Cosine released an analysis report on the Balancer hack exceeding 100 millions USD. The report pointed out that the root cause lies in the implementation of Balancer v2's Composable Stable Pool (based on Curve StableSwap's Stable Math), where there is a precision loss issue in the integer fixed-point calculation of scalingFactors. This leads to small but compounding price differences/errors during token swaps. Attackers exploited this by conducting small swaps under low liquidity to amplify these errors for significant cumulative profits.