Summary
dset vulnerable to prototype pollution
Overview
Prototype pollution vulnerability in 'dset' versions 1.0.0 through 2.0.1 allows attacker to cause a denial of service and may lead to remote code execution.
Details
The NPM module 'dset' can be abused by Prototype Pollution vulnerability since the function ‘export ()' did not check for the type of object before assigning value to the property. Due to this flaw an attacker could create a non-existent property or able to manipulate the property which leads to Denial of Service or potentially Remote code execution.
PoC
The export function accepts three arguments obj, keys, val. Due to the absence of validation, at values passed into keys, val arguments, an attacker can supply a malicious value by adjusting the keys value to include the __proto__ property. Since there is no validation before assigning property to check whether the assigned keys is the Object's own property or not, the property isAdmin will be directly be assigned to the empty obj({}) thereby polluting the Object prototype. Later in the code, if there is a check to validate isAdmin the valued would be substituted as "true" as it had been polluted.
const dset = require('dset');
var obj = {}
console.log("Before : " + obj.isAdmin);
dset(obj, '__proto__.polluted', true);
console.log("After : " + obj.polluted);
Impact
CVE-2020-28277 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no 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 (2.0.1); 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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Frequently Asked Questions
- What is CVE-2020-28277? CVE-2020-28277 is a critical-severity security vulnerability in dset (npm), affecting versions >= 1.0.0, < 2.0.1. It is fixed in 2.0.1.
- How severe is CVE-2020-28277? CVE-2020-28277 has a CVSS score of 9.8 (Critical). 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 dset are affected by CVE-2020-28277? dset (npm) versions >= 1.0.0, < 2.0.1 is affected.
- Is there a fix for CVE-2020-28277? Yes. CVE-2020-28277 is fixed in 2.0.1. Upgrade to this version or later.
- Is CVE-2020-28277 exploitable, and should I be worried? Whether CVE-2020-28277 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-2020-28277 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-2020-28277? Upgrade
dsetto 2.0.1 or later.