CVE-2021-23373Public exploitNetwork attack vector

Prototype pollution via unchecked property paths

Published Jul 25, 2022 · Updated Sep 16, 2024

Prototype pollution in set-deep-prop 1.0.0 and earlier allows attackers to modify Object.prototype through a crafted property path. The exported setDeepProp function traverses supplied path segments without blocking proto, then assigns the supplied value to the inherited object. Exploitation requires a consuming application to pass attacker-controlled path elements; polluted properties can alter later object behavior or crash the application.

CVSS severity9.8
Critical
EPSS probability1.13%
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 set-deep-prop 1.0.0 and earlier allows attackers to modify Object.prototype through a crafted property path. The exported setDeepProp function traverses supplied path segments without blocking proto, then assigns the supplied value to the inherited object. Exploitation requires a consuming application to pass attacker-controlled path elements; polluted properties can alter later object behavior or crash the application.

The record

CVE
CVE-2021-23373
Published
Jul 25, 2022
Updated
Sep 16, 2024
Vendor
mmckelvy
Product
set-deep-prop
Classifications
CWE-1321, CAPEC-1, CAPEC-180, CAPEC-77
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 2022CVE 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?

mmckelvy · set-deep-propversion=0 <unspecified

Published CVSS scores

7.5SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
CAPEC-1Accessing Functionality Not Properly Constrained by ACLs
CAPEC-180Exploiting Incorrectly Configured Access Control Security Levels
CAPEC-77Manipulating User-Controlled Variables

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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