Summary
Prototype Pollution in hoek
Versions of hoek prior to 4.2.1 and 5.0.3 are vulnerable to prototype pollution.
The merge function, and the applyToDefaults and applyToDefaultsWithShallow functions which leverage merge behind the scenes, are vulnerable to a prototype pollution attack when provided an unvalidated payload created from a JSON string containing the __proto__ property.
This can be demonstrated like so:
var Hoek = require('hoek');
var malicious_payload = '{"__proto__":{"oops":"It works !"}}';
var a = {};
console.log("Before : " + a.oops);
Hoek.merge({}, JSON.parse(malicious_payload));
console.log("After : " + a.oops);
This type of attack can be used to overwrite existing properties causing a potential denial of service.
Impact
CVE-2018-3728 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.0.3, 4.2.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Update to version 4.2.1, 5.0.3 or later.
Frequently Asked Questions
- What is CVE-2018-3728? CVE-2018-3728 is a high-severity security vulnerability in hoek (npm), affecting versions >= 5.0.0, < 5.0.3. It is fixed in 5.0.3, 4.2.1.
- How severe is CVE-2018-3728? CVE-2018-3728 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of hoek are affected by CVE-2018-3728? hoek (npm) versions >= 5.0.0, < 5.0.3 is affected.
- Is there a fix for CVE-2018-3728? Yes. CVE-2018-3728 is fixed in 5.0.3, 4.2.1. Upgrade to this version or later.
- Is CVE-2018-3728 exploitable, and should I be worried? Whether CVE-2018-3728 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2018-3728 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2018-3728?
- Upgrade
hoekto 5.0.3 or later - Upgrade
hoekto 4.2.1 or later
- Upgrade