CVE-2023-42460
MEDIUMCVE-2023-42460 is a medium-severity (CVSS 5.3) CWE-682 vulnerability in vyper. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2023-42460 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
_abi_decode input not validated in complex expressions in Vyper
Blast Radius
vyperReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Vyper is a Pythonic Smart Contract Language for the EVM. The _abi_decode() function does not validate input when it is nested in an expression. Uses of _abi_decode() can be constructed which allow for bounds checking to be bypassed resulting in incorrect results. This issue has not yet been fixed, but a fix is expected in release 0.3.10. Users are advised to reference pull request #3626.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | ≥ 0.3.4&&< 0.3.10 | 0.3.10 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vyper. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update vyper to 0.3.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-42460 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-42460 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-42460. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-42460 in your dependencies?
O3 detects CVE-2023-42460 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.