CVE-2026-24888: Makerjs Maker.js Has Unsafe Property Copying Vulnerability
MODERATECVE-2026-24888 is a MODERATE (CVSS 6.5) maker.js has unsafe property copying vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Makerjs libraries in the npm ecosystem. The issue involves maker.js has unsafe property copying in makerjs.extendobject. Remediation is available by upgrading affected packages to version 0.19.2.
CVE-2026-24888 at a Glance
Security Impact
CVSS: 6.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N).
How to Fix CVE-2026-24888
To remediate this vulnerability, upgrade all affected Makerjs dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install makerjs@0.19.2Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls makerjsHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-24888, inspect your project dependencies using npm:
npm ls makerjsAnalyze the terminal output to locate any version of Makerjs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.19.2), your application is affected.
Note: The npm ls makerjs command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Makerjs, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-24888 Affected Makerjs Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
makerjs
|
npm |
< 0.19.2
|
0.19.2
|
References
Frequently Asked Questions
What is CVE-2026-24888?
Which Makerjs versions are affected?
What version fixes CVE-2026-24888?
Is makerjs affected?
What is the CVSS score of CVE-2026-24888?
What CWE is associated with CVE-2026-24888?
How can I check npm dependencies for CVE-2026-24888?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-2cp6-34r9-54xx",
"modified" : "2026-01-29T15:18:33Z",
"published" : "2026-01-29T15:18:33Z",
"aliases" : [ "CVE-2026-24888" ],
"summary" : "Maker.js has Unsafe Property Copying in makerjs.extendObject",
"details" : "### Summary\nThe `makerjs.extendObject` function copies properties from source objects without proper validation, potentially exposing applications to security risks. The function lacks `hasOwnProperty()` checks and does not filter dangerous keys, allowing inherited properties and potentially malicious properties to be copied to target objects.\n\n### Details\nThe `extendObject` function iterates over source object properties using a `for...in` loop without:\n1. Checking `hasOwnProperty()` to exclude inherited properties\n2. Filtering dangerous keys (`__proto__`, `constructor`, `prototype`)\n3. Validating property sources\n\n### Affected Code\n\n**File**: https://github.com/microsoft/maker.js/blob/98cffa82a372ff942194c925a12a311253587167/packages/maker.js/src/core/maker.ts#L232-L241\n\n\n\n### PoC\n```javascript\nconst makerjs = require('makerjs');\n\nconst source = { __proto__: { name: 'Ravi', isAdmin: true } };\nconst target = { name: 'user' };\nconst result = makerjs.extendObject(target, source);\n\nconsole.log(result.name); // Ravi\nconsole.log(result.isAdmin); // true\n```\n\n\n### Impact\n### Security Implications\n\n1. **Unexpected Behavior**: Properties may appear on target objects but not be own properties, breaking `hasOwnProperty()` assumptions in security-sensitive code.\n\n2. **Security Bypass Risk**: Code relying on `hasOwnProperty()` for validation could be bypassed.\n\n3. **Future Risk**: Lack of dangerous key filtering (`__proto__`, `constructor`, `prototype`) exposes potential attack vectors.\n\n### Affected Use Cases\n\n- Extending objects from user input or external APIs\n- Merging options from untrusted sources",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "makerjs"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.19.2"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 0.19.1"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/microsoft/maker.js/security/advisories/GHSA-2cp6-34r9-54xx"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24888"
}, {
"type" : "WEB",
"url" : "https://github.com/microsoft/maker.js/commit/85e0f12bd868974b891601a141974f929dec36b8"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/microsoft/maker.js"
}, {
"type" : "WEB",
"url" : "https://github.com/microsoft/maker.js/blob/98cffa82a372ff942194c925a12a311253587167/packages/maker.js/src/core/maker.ts#L232-L241"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-1321" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-01-29T15:18:33Z",
"nvd_published_at" : "2026-01-28T22:15:56Z"
}
}