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Fencer Intel
high 7.5

CVE-2020-8268 json

Prototype pollution in json8-merge-patch

published 6y ago modified 4mo ago also GHSA-8v9x-9xqg-r8mr , EUVD-2021-1022

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

Prototype pollution vulnerability in json8-merge-patch npm package < 1.0.3 may allow attackers to inject or modify methods and properties of the global object constructor.

Patch / fix

  • npm json8-merge-patch 1.0.3
  • json8-merge-patch_project json8-merge-patch 1.0.3

Is CVE-2020-8268 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.

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Exploit prediction

1.29% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/980649 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm json8-merge-patch
<1.0.3
1.0.3

Affected products

  • n/a json8-merge-patch

Classification

Weakness
  • CWE-471 Modification of Assumed-Immutable Data (MAID)
  • CWE-20 Improper Input Validation
  • CWE-1321 Improperly Controlled Modification of Object Prototype 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.