Prototype Pollution in defaults-deep

published 2019-02-01 7 y ago modified 2026-06-17 4 mo ago also GHSA-pjxw-22xf-6pwc , EUVD-2019-0323

cvss: 9.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.5%; EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits: 0; none known

A prototype pollution vulnerability was found in defaults-deep <=0.2.4 that would allow a malicious user to inject properties onto Object.prototype.

Exploit prediction

1.48% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

hackerone.com https://hackerone.com/reports/380878 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.0	9.8	CVSS:3.0/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	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	defaults-deep	<=0.2.4	no fix listed

Affected products

HackerOne defaults-deep

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
CWE-345 Insufficient Verification of Data Authenticity

References

hackerone.com /reports/380878
web, exploit, issue-tracking, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2018-16486
advisory
github.com /advisories/GHSA-pjxw-22xf-6pwc
advisory
github.com /jonschlinkert/defaults-deep
package
npmjs.com /advisories/778
web

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary