Skip to content
Fencer Vulns
critical 9.8

CVE-2020-28279 json

flattenizer vulnerable to prototype pollution

published 2020-12-29 5 y ago modified 2026-06-17 4 mo ago also GHSA-vq33-26pr-r4h6 , EUVD-2022-5400

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.1%
EPSS 3.1% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

Prototype pollution vulnerability in 'flattenizer' versions 0.0.5 through 1.0.5 allows an attacker to cause a denial of service and may lead to remote code execution.

Patch / fix

  • npm flattenizer 1.1.1

Exploit prediction

3.11% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sahellebusch/flattenizer/pull/13 referenced PoC, tagged "exploit" by a source, unverified

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 flattenizer
>=0.0.5, <1.1.1
1.1.1

Affected products

  • n/a flattenizer

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

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.