CVE-2026-84368Network attack vectorHinoki check available

Prototype pollution via inherited custom-message language objects

Published Sep 1, 2026 · Updated Sep 2, 2026

Prototype pollution in @hapi/joi through 17.1.1, joi 17 before 17.13.6, and joi 18 before 18.2.5 lets attackers alter objects via custom messages. In lib/messages.js, exports.compile() and exports.merge() reuse inherited objects for attacker-controlled language keys, writing onto Object.prototype or Object function properties. Reachability requires a consuming application to pass untrusted input into schema-construction configuration; validated data alone cannot trigger the flaw, while successful pollution changes property tests process-wide.

CVSS severity3.7
Low
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Prototype pollution in @hapi/joi through 17.1.1, joi 17 before 17.13.6, and joi 18 before 18.2.5 lets attackers alter objects via custom messages. In lib/messages.js, exports.compile() and exports.merge() reuse inherited objects for attacker-controlled language keys, writing onto Object.prototype or Object function properties. Reachability requires a consuming application to pass untrusted input into schema-construction configuration; validated data alone cannot trigger the flaw, while successful pollution changes property tests process-wide.

The record

CVE
CVE-2026-84368
Published
Sep 1, 2026
Updated
Sep 2, 2026
Vendor
hapi.js
Product
joi
Classifications
CWE-1321, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 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?

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

  1. Affected versionversion=>= 16.0.0, <= 17.1.1
  2. Affected versionversion=>= 17.2.0, < 17.13.6
  3. Affected versionversion=>= 18.0.0, < 18.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

hapi.js · joiversion=>= 16.0.0, <= 17.1.1; version=>= 17.2.0, < 17.13.6; version=>= 18.0.0, < 18.2.5

Published CVSS scores

3.7GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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