Prototype Pollution in just-extend

Also known as GHSA-675m-85rw-j3w4

Published 7 y ago 2019-02-01 · modified 4 mo ago 2026-06-17 · JSON

CVSS

9.8

v3.1 · NVD

CISA KEV

not known exploited

EPSS

1.8%

percentile 79%

Public exploits

none known

A prototype pollution vulnerability was found in just-extend <4.0.0 that allows attack to inject properties onto Object.prototype through its functions.

Exploit prediction (EPSS)

1.84% probability of exploitation in the next 30 days, higher than 79% of all scored CVEs.

CVSS scores

Assigned by	Version	Score	Vector
NVD	3.1	9.8	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
NVD	2.0	7.5	`AV:N/AC:L/Au:N/C:P/I:P/A:P`
GitHub	3.1	9.8	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

Affected packages

Ecosystem	Package	Affected	Fixed in
npm	`just-extend`	<4.0.0	4.0.0

Affected products

HackerOne just-extend

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

hackerone.com /reports/430291 · x_refsource_MISC, x_transferred
nvd.nist.gov /vuln/detail/CVE-2018-16489 · advisory
github.com /advisories/GHSA-675m-85rw-j3w4 · advisory
npmjs.com /advisories/780 · web

Sources

CVE List: CVE-2018-16489
GitHub Advisory: GHSA-675m-85rw-j3w4
NVD: CVE-2018-16489

vulnwire keeps one entry per vulnerability: the CVE id wins, then GHSA; records that alias each other are merged. Machine-readable: JSON.

Summary