CVE-2026-24888 is a medium-severity (CVSS 6.5) CWE-1321 vulnerability in makerjs. A fix is available for makerjs — see the affected versions and patch details below.
Maker.js Vulnerable to Unsafe Property Copying in makerjs.extendObject
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-24888.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
makerjsnpmDescription
Summary
The 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.
Details
The extendObject function iterates over source object properties using a for...in loop without:
- Checking
hasOwnProperty()to exclude inherited properties - Filtering dangerous keys (
__proto__,constructor,prototype) - Validating property sources
Affected Code
PoC
const makerjs = require('makerjs');
const source = { __proto__: { name: 'Ravi', isAdmin: true } };
const target = { name: 'user' };
const result = makerjs.extendObject(target, source);
console.log(result.name); // Ravi
console.log(result.isAdmin); // true
Impact
Security Implications
-
Unexpected Behavior: Properties may appear on target objects but not be own properties, breaking
hasOwnProperty()assumptions in security-sensitive code. -
Security Bypass Risk: Code relying on
hasOwnProperty()for validation could be bypassed. -
Future Risk: Lack of dangerous key filtering (
__proto__,constructor,prototype) exposes potential attack vectors.
Affected Use Cases
- Extending objects from user input or external APIs
- Merging options from untrusted sources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | makerjs | all versions | 0.19.2npm install makerjs@0.19.2 |
Affected Products
maker.jsmicrosoftDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for makerjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update makerjs to 0.19.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-24888 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-24888 in your dependencies?
Find it across npm, including transitive dependencies.