joi: object().rename() with a template target can set the validated object's prototype

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-84367
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-01 21:18:47 UTC
Updated2026-09-01 21:18:47 UTC
Descriptionjoi is a schema description language and data validator for JavaScript. From 16.0.0 until 17.13.5 and 18.2.4, joi's lib/types/keys.js internals.rename() implementation used by object().rename() permits a schema that renames keys with a regular-expression source and a Joi.expression() or Joi.x() target that interpolates the pattern's own match data, combined with { multiple: true }, to derive a target from an attacker-controlled input key. An attacker can send x-__proto__ with an object value, causing the target to render as __proto__ and set the prototype of the object returned by validate() instead of creating an own key. The global Object.prototype is not modified, so the effect is confined to the object returned by that validation call. Static-string targets and schemas using the default { multiple: false } are not affected. This issue is fixed in versions 17.13.5 and 18.2.4.

Risk And Classification

Primary CVSS: v3.1 3.7 LOW from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS: 0.002700000 probability, percentile 0.188150000 (date 2026-09-02)

Problem Types: CWE-1321 | CWE-1321 CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Hapijs Joi affected >= 16.0.0, < 17.13.5 Not specified
CNA Hapijs Joi affected >= 18.0.0, < 18.2.4 Not specified

References

ReferenceSourceLinkTags
github.com/hapijs/joi/pull/3134 [email protected] github.com
github.com/hapijs/joi/commit/172ececa192feda532b743d77bc9d3e523d19b01 [email protected] github.com
github.com/hapijs/joi/security/advisories/GHSA-gg4h-3hg2-grpc [email protected] github.com
github.com/hapijs/joi/commit/162f367aa178d2e1ebec8dc1164e5fe16536ddf6 [email protected] github.com
github.com/hapijs/joi/pull/3135 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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