CVE-2023-42460
MEDIUM5.3EPSS 0.05%Vyper's `_abi_decode` input not validated in complex expressions
Description
### 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 (2)
- PyPI/vyper>= 0.3.4, < 0.3.10
- PyPI/vyper>= 0.3.4, < 0.3.10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N |
References (5)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2023-42460
- PATCHhttps://github.com/vyperlang/vyper
- WEBhttps://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-191.yaml
- WEBhttps://github.com/vyperlang/vyper/pull/3626
- WEBhttps://github.com/vyperlang/vyper/security/advisories/GHSA-cx2q-hfxr-rj97