GHSA-4hg4-9mf5-wxxq
MEDIUMincorrect order of evaluation of side effects for some builtins
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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
Impact
The order of evaluation of the arguments of the builtin functions uint256_addmod, uint256_mulmod, ecadd and ecmul does not follow source order.
• For uint256_addmod(a,b,c) and uint256_mulmod(a,b,c), the order is c,a,b.
• For ecadd(a,b) and ecmul(a,b), the order is b,a.
Note that this behaviour is problematic when the evaluation of one of the arguments produces side effects that other arguments depend on.
Patches
https://github.com/vyperlang/vyper/pull/3583
Workarounds
When using builtins from the list above, make sure that the arguments of the expression do not produce side effects or, if one does, that no other argument is dependent on those side effects.
References
Are there any links users can visit to find out more?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | all versions | 0.3.10rc1 |
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 0.3.10rc1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4hg4-9mf5-wxxq 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 GHSA-4hg4-9mf5-wxxq 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 GHSA-4hg4-9mf5-wxxq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4hg4-9mf5-wxxq in your dependencies?
O3 detects GHSA-4hg4-9mf5-wxxq across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.