CVE-2018-3728 is a high-severity (CVSS 8.8) CWE-471 vulnerability in hoek. 2 public exploit references exist, so weaponization risk is real. A fix is available for hoek — see the affected versions and patch details below.
Prototype Pollution in hoek
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.
How urgent is this, really
CVE-2018-3728 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
hoeknpmDescription
hoek node module before 4.2.0 and 5.0.x before 5.0.3 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability via 'merge' and 'applyToDefaults' functions, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hoek | ≥ 5.0.0&&< 5.0.3 | 5.0.3npm install hoek@5.0.3 |
| 📦npm | hoek | all versions | 4.2.1npm install hoek@4.2.1 |
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 hoek, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hoek to 5.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-3728 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2018-3728 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-3728. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat Quay includes hoek as a dependency of protractor which is only used at build time. The vulnerable library is not used at runtime meaning this has a low impact on Red Hat Quay.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Mobile Application Platform 4.6 | fh-system-dump-tool-0:1.0.0-5.el7 | RHSA-2018:1263 |
| Red Hat Mobile Application Platform 4.6 | rhmap46/fh-aaa:1.1.3-4 | RHSA-2018:1264 |
| Red Hat Quay 3 | quay/quay-rhel8:v3.6.0-62 | RHSA-2021:3917 |
Frequently Asked Questions
Is CVE-2018-3728 in your dependencies?
O3 Security finds CVE-2018-3728 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.