GHSA-vxmm-cwh2-q762
Vyper's nonpayable default functions are sometimes payable
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
### Impact
in contracts with at least one regular nonpayable function, due to the callvalue check being inside of the selector section, it is possible to send funds to the default function by using less than 4 bytes of calldata, even if the default function is marked `nonpayable`. this applies to contracts compiled with vyper<=0.3.7.
```vyper
# @version 0.3.7
# implicitly nonpayable
@external
def foo() -> uint256:
return 1
# implicitly nonpayable
@external
def __default__():
# could receive ether here
pass
```
### Patches
this was fixed by the removal of the global calldatasize check in https://github.com/vyperlang/vyper/commit/02339dfda0f3caabad142060d511d10bfe93c520.
### Workarounds
don't use nonpayable default functions
References
External links from the advisory. They lead to third-party sites.
- https://github.com/vyperlang/vyper/security/advisories/GHSA-vxmm-cwh2-q762
- https://nvd.nist.gov/vuln/detail/CVE-2023-32675
- https://github.com/vyperlang/vyper/commit/02339dfda0f3caabad142060d511d10bfe93c520
- https://github.com/vyperlang/vyper/commit/02339dfda0f3caabad142060d511d10bfe93c520.
- https://github.com/vyperlang/vyper/commit/903727006c1e5ebef99fa9fd5d51d62bd33d72a9
- https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-80.yaml
- https://github.com/vyperlang/vyper