CVE-2023-49798 is a medium-severity (CVSS 5.9) CWE-670 vulnerability in @openzeppelin/contracts. O3 Security confirms whether CVE-2023-49798 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Duplicated execution of subcalls in OpenZeppelin Contracts
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@openzeppelin/contractsnpm@openzeppelin/contracts-upgradeablenpmDescription
OpenZeppelin Contracts is a library for smart contract development. A merge issue when porting the 5.0.1 patch to the 4.9 branch caused a line duplication. In the version of Multicall.sol released in @openzeppelin/[email protected] and @openzeppelin/[email protected], all subcalls are executed twice. Concretely, this exposes a user to unintentionally duplicate operations like asset transfers. The duplicated delegatecall was removed in version 4.9.5. The 4.9.4 version is marked as deprecated. Users are advised to upgrade. There are no known workarounds for this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @openzeppelin/contracts | ≥ 4.9.4&&< 4.9.5 | 4.9.5 |
| 📦npm | @openzeppelin/contracts-upgradeable | ≥ 4.9.4&&< 4.9.5 | 4.9.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @openzeppelin/contracts. 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 @openzeppelin/contracts to 4.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49798 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-2023-49798 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-2023-49798. 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-2023-49798 in your dependencies?
O3 detects CVE-2023-49798 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.