Prototype Pollution

published 2020-08-17 6 y ago modified 2026-06-17 4 mo ago also GHSA-gr58-j5wh-m333 , EUVD-2021-1084

cvss: 9.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.9%; EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits: 0; none known

All versions of package nis-utils are vulnerable to Prototype Pollution via the setValue function.

Exploit prediction

1.93% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

snyk.io https://snyk.io/vuln/SNYK-JS-NISUTILS-598799 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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	nis-utils	<=0.6.10	no fix listed

Affected products

n/a nis-utils

Classification

Weakness

CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes

References

snyk.io /vuln/SNYK-JS-NISUTILS-598799
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2020-7703
advisory

Sources

CVE List CVE-2020-7703
GitHub Advisory GHSA-gr58-j5wh-m333
NVD CVE-2020-7703

Fencer Vulns 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