CVE-2021-23442Public exploitNetwork attack vector

Object-prototype pollution via unfiltered recursive assignment

Published Sep 17, 2021 · Updated Sep 16, 2024

Prototype pollution in @cookiex/deep before 0.0.7 allows remote attackers to modify Object.prototype through crafted input objects. The Assigner loop recursively copies every enumerable source key and, before the patch, fails to reject proto, constructor, or prototype. Exploitation requires a consuming application to pass attacker-controlled object data into the library; polluted inherited properties can alter application behavior.

CVSS severity8.6
High
EPSS probability1.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in @cookiex/deep before 0.0.7 allows remote attackers to modify Object.prototype through crafted input objects. The Assigner loop recursively copies every enumerable source key and, before the patch, fails to reject proto, constructor, or prototype. Exploitation requires a consuming application to pass attacker-controlled object data into the library; polluted inherited properties can alter application behavior.

The record

CVE
CVE-2021-23442
Published
Sep 17, 2021
Updated
Sep 16, 2024
Vendor
tony-tsx
Product
@cookiex/deep
Classifications
CWE-915, CWE-1321
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

tony-tsx · @cookiex/deepversion=0 <unspecified

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.6GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-915Improperly Controlled Modification of Dynamically-Determined Object Attributes
CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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