Skip to content
Fencer Intel
medium 5.6

CVE-2021-23417 json

Prototype Pollution

published 5y ago modified 4mo ago also GHSA-vj72-mwrj-m2xq , EUVD-2021-1894

cvss
5.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

All versions of package deepmergefn are vulnerable to Prototype Pollution via deepMerge function.

Is CVE-2021-23417 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

1.08% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-JS-DEEPMERGEFN-1310984 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:U/RC:C
CNA 3.1 5.6 CVSS:3.1/AV:N/AC:H/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
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
npm deepmergefn
<=1.1.0
 no fix listed

Affected products

  • n/a deepmergefn

Classification

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

References

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.