CVE-2023-38894Public exploitNetwork attack vector

Code execution via unflat prototype pollution

Published Aug 16, 2023 · Updated Jul 9, 2026

Prototype pollution in Cronvel tree-kit 0.7.4 and earlier allows remote attackers to execute code through crafted input to extend(). With unflat enabled, extend() treats attacker-controlled dotted keys such as constructor.prototype.polluted as object paths and writes through them into Object.prototype. A consuming application must pass untrusted objects to this non-default mode; polluted properties can alter application behavior, enabling code execution or a service crash when suitable application paths use them.

CVSS severity9.8
Critical
EPSS probability1.69%
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 Cronvel tree-kit 0.7.4 and earlier allows remote attackers to execute code through crafted input to extend(). With unflat enabled, extend() treats attacker-controlled dotted keys such as constructor.prototype.polluted as object paths and writes through them into Object.prototype. A consuming application must pass untrusted objects to this non-default mode; polluted properties can alter application behavior, enabling code execution or a service crash when suitable application paths use them.

The record

CVE
CVE-2023-38894
Published
Aug 16, 2023
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1321, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS: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')
T1190Exploit Public-Facing Application

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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