CVE-2024-21505
HIGHCVE-2024-21505 is a high-severity (CVSS 7.5) CWE-1321 vulnerability in web3-utils. O3 Security confirms whether CVE-2024-21505 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
web3-utils Prototype Pollution vulnerability
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
web3-utilsnpmDescription
Versions of the package web3-utils before 4.2.1 are vulnerable to Prototype Pollution via the utility functions format and mergeDeep, due to insecure recursive merge. An attacker can manipulate an object's prototype, potentially leading to the alteration of the behavior of all objects inheriting from the affected prototype by passing specially crafted input to these functions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | web3-utils | ≥ 4.0.1&&< 4.2.1 | 4.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web3-utils. 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 web3-utils to 4.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21505 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-2024-21505 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-2024-21505. 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-2024-21505 in your dependencies?
O3 detects CVE-2024-21505 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.