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Fencer Vulns
high 7.3

CVE-2023-26135 json

flatnest Prototype Pollution vulnerability

published 2023-06-30 3 y ago modified 2026-06-17 4 mo ago also GHSA-7px2-3c2p-q4v4 , EUVD-2023-1736

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

All versions of the package flatnest are vulnerable to Prototype Pollution via the nest() function in the flatnest/nest.js file.

Patch / fix

Exploit prediction

0.89% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • security.snyk.io https://security.snyk.io/vuln/SNYK-JS-FLATNEST-3185149 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/brycebaril/node-flatnest/issues/4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
npm flatnest
<=1.0.0
 no fix listed

Affected products

  • n/a flatnest

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.