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Prototype Pollution in jquery-deparam

High severity GitHub Reviewed Published May 24, 2021 to the GitHub Advisory Database • Updated Aug 14, 2025

Package

npm jquery-deparam (npm)

Affected versions

<= 0.5.3

Patched versions

None

Description

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

References

Published by the National Vulnerability Database Apr 23, 2021
Reviewed May 20, 2021
Published to the GitHub Advisory Database May 24, 2021
Last updated Aug 14, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(82nd percentile)

Weaknesses

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. Learn more on MITRE.

CVE ID

CVE-2021-20087

GHSA ID

GHSA-xg68-chx2-253g

Source code

No known source code
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