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Fencer Vulns
high 8.8

CVE-2021-20083 json

jquery-plugin-query-object contains prototype pollution vulnerability

published 2021-04-23 5 y ago modified 2026-06-17 4 mo ago also GHSA-q9xg-h756-8689 , EUVD-2022-4938

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.2%
EPSS 4.2% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in jquery-plugin-query-object 2.2.3 allows a malicious user to inject properties into Object.prototype.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20083 updated cvss 8.8

wordpress: WordPress Core 5.9.0 / 5.9.1 Cross Site Scripting

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.19% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/BlackFan/client-side-prototype-pollution/blob/master/pp/jquery-query-object.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm jquery-query-object
<=2.2.3
 no fix listed

Affected products

  • n/a jquery-plugin-query-object

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.