Submitted by KingNFT, also found by lukejohn, 0xmystery, DimaKush, vnavascues, Matue, adamn000, Kose, 0xDemon (1, 2), jacopod, 0xStalin, MrPotatoMagic, 42TechLabs, oxTory, nnez, yixxas, ktg, thank_you, ubermensch, opposingmonkey, nonseodion, btk, matejdb, 0xc0ffEE, salutemada, novodelta, zhaojie, _eperezok, sl1, mrudenko, PENGUN, osmanozdemir1, spacelord47, mahdirostami, DarkTower, InAllHonesty, SpicyMeatball, alexfilippov314 (1, 2), oreztker, Timenov, zhaojohnson, eeshenggoh, SovaSlava, dimulski, UbiquitousComputing, cats, Soliditors, nmirchev8, darksnow, BugzyVonBuggernaut, hals, ke1caM, peanuts, EV_om, cccz, bronze_pickaxe, OMEN, 0xMAKEOUTHILL, aslanbek, israeladelaja, Kow, and haxatron, 
Any CurveSubjects clould be turned to a HoneyPot by the creator of CurveSubject, which causes that users can only buy but cant sell the curve tokens any more. Then malicious creators can sell their own tokens at a high price to make profit.
By exploiting the above two facts, we can design the following malicious EvilReferralFeeReceiver contract. Once it was set as ReferralFeeDestination, the HoneyPot mode is enabled, users can only buy but cant sell the related curve tokens any more.
The full coded PoC:
The test logs:
Soladys forceSafeTransferETH() seems suitable for this case:
https://github.com/Vectorized/solady/blob/61612f187debb7affbe109543556666ef716ef69/src/utils/SafeTransferLib.sol#L117
andresaiello (Curves) confirmed
alcueca (Judge) commented:
