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The vulnerability CVE-2025-4255 exists in the `lib.set` function of dref version 0.1.2. This function is designed to set nested property values within an object using a path string. The flaw arises from inadequate sanitization of this path input. An attacker can supply a crafted payload containing special sequences like `__proto__` or `constructor.prototype` as part of the path. When the vulnerable `lib.set` function processes this path, it incorrectly traverses and modifies the Object prototype instead of the target object. By polluting the prototype, the attacker can inject properties into all objects in the application. This can lead to a Denial of Service (DoS) by altering the behavior of critical object methods or causing exceptions that crash the application when certain properties are accessed or modified.
Platform: Node.js
Version: 0.1.2
Vulnerability: Prototype Pollution
Severity: High
date: 2025-09-25
Prediction: Patch by 2025-10-02
What Undercode Say:
npm list dref
const dref = require('dref');
// Malicious payload triggering the pollution
const malicious_payload = "<strong>proto</strong>.polluted";
dref.set({}, malicious_payload, "yes");
// Confirming pollution
console.log(({}).polluted); // Outputs 'yes'
How Exploit:
An attacker crafts a request or input containing a path like `__proto__.status` with a value that overrides a fundamental method, causing the application to enter an infinite loop or throw an unhandled exception when that property is used, resulting in a crash.
Protection from this CVE
Immediately upgrade dref to a patched version once available. As a temporary mitigation, validate and sanitize all input objects and paths to reject keys containing __proto__, constructor, or prototype.
Impact:
Denial of Service (DoS) by making the application unstable or unresponsive through prototype pollution.
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Sources:
Reported By: github.com
Extra Source Hub:
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