Weakness in Transfer Validation Logic in @solana/pay

Solana Pay is a protocol and set of reference implementations that enable developers to incorporate decentralized payments into their apps and services. When a Solana Pay transaction is located using a reference key, it may be checked to represent a transfer of the desired amount to the recipient, using the supplied `validateTransfer` function. An edge case regarding this mechanism could cause the validation logic to validate multiple transfers. This issue has been patched as of version `0.2.1`. Users of the Solana Pay SDK should upgrade to it. There are no known workarounds for this issue.