CVE-2023-42460
Vyper's `_abi_decode` input not validated in complex expressions
Impact
### Impact `_abi_decode()` does not validate input when it is nested in an expression. the following example gets correctly validated (bounds checked): ```vyper x: int128 = _abi_decode(slice(msg.data, 4, 32), int128) ``` however, the following example is not bounds checked ```vyper @external def abi_decode(x: uint256) -> uint256: a: uint256 = convert(_abi_decode(slice(msg.data, 4, 32), (uint8)), uint256) + 1 return a # abi_decode(256) returns: 257 ``` the issue can be triggered by constructing an example where the output of `_abi_decode` is not internally passed to `make_setter` (an internal codegen routine) or other input validating routine. ### Patches https://github.com/vyperlang/vyper/pull/3626 ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References _Are there any links users can visit to find out more?_
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | vyper | >= 0.3.4, < 0.3.10 | 0.3.10 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Vyperlang | Vyper | from 0.3.4 before 0.3.10 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/vyperlang/vyper/pull/3626
- https://github.com/vyperlang/vyper/security/advisories/GHSA-cx2q-hfxr-rj97
- https://github.com/advisories/GHSA-cx2q-hfxr-rj97
- https://nvd.nist.gov/vuln/detail/CVE-2023-42460
- https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-191.yaml