_Submitted by shw, also found by gpersoon, 0xRajeev and pauliax__
The YearnV2YieldSource contract prevents the supplyTokenTo, redeemToken, and sponsor functions from being reentered by applying a nonReentrant modifier. Since these contracts share a similar logic, adding a nonReentrant modifier to these functions in all of the yield source contracts is reasonable. However, the same protection is not seen in other yield source contracts.
A nonReentrant modifier in the following functions is missing:
Recommend adding a nonReentrant modifier to these functions. For BadgerYieldSource and SushiYieldSource contracts, make them inherit from Openzeppelins ReentrancyGuardUpgradeable to use the nonReentrant modifier.
kamescg (PoolTogether) confirmed and patched:
