Submitted by gogo, also found by V_B and taek
User operations can be replayed on smart accounts accross different chains. This can lead to users losing funds or any unexpected behaviour that transaction replay attacks usually lead to.
As specified by the EIP4337 standard to prevent replay attacks ... the signature should depend on chainid. In VerifyingSingletonPaymaster.sol#getHash the chainId is missing which means that the same UserOperation can be replayed on a different chain for the same smart contract account if the verifyingSigner is the same (and most likely this will be the case).
Add the chainId in the calculation of the UserOperation hash in VerifyingSingletonPaymaster.sol#getHash
livingrockrises (Biconomy) confirmed
gzeon (judge) decreased severity to Medium
vlad_bochok (warden) commented:
livingrockrises (Biconomy) commented:
