CVE-2023-30629
HIGHCVE-2023-30629 is a high-severity (CVSS 7.5) CWE-670 vulnerability in vyper. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2023-30629 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Vyper's raw_call with outsize=0 and revert_on_failure=False returns incorrect success value
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 ethereum virtual machine. In versions 0.3.1 through 0.3.7, the Vyper compiler generates the wrong bytecode. Any contract that uses the raw_call with revert_on_failure=False and max_outsize=0 receives the wrong response from raw_call. Depending on the memory garbage, the result can be either True or False. A patch is available and, as of time of publication, anticipated to be part of Vyper 0.3.8. As a workaround, one may always put max_outsize>0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | ≥ 0.3.1&&< 0.3.8 | 0.3.8 |
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 0.3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-30629 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-2023-30629 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-2023-30629. 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-2023-30629 in your dependencies?
O3 detects CVE-2023-30629 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.