CVE-2026-84367 (GCVE-0-2026-84367)
Vulnerability from cvelistv5 – Published: 2026-09-01 20:33 – Updated: 2026-09-01 20:33
VLAI
EPSS
VEX
Title
joi: object().rename() with a template target can set the validated object's prototype
Summary
joi 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.
Severity
CWE
- CWE-1321 - Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/hapijs/joi/security/advisories… | x_refsource_CONFIRM |
| https://github.com/hapijs/joi/pull/3134 | x_refsource_MISC |
| https://github.com/hapijs/joi/pull/3135 | x_refsource_MISC |
| https://github.com/hapijs/joi/commit/162f367aa178… | x_refsource_MISC |
| https://github.com/hapijs/joi/commit/172ececa192f… | x_refsource_MISC |
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"product": "joi",
"vendor": "hapijs",
"versions": [
{
"status": "affected",
"version": "\u003e= 16.0.0, \u003c 17.13.5"
},
{
"status": "affected",
"version": "\u003e= 18.0.0, \u003c 18.2.4"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "joi is a schema description language and data validator for JavaScript. From 16.0.0 until 17.13.5 and 18.2.4, joi\u0027s 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\u0027s 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."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 3.7,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-1321",
"description": "CWE-1321: Improperly Controlled Modification of Object Prototype Attributes (\u0027Prototype Pollution\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-01T20:33:29.295Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/hapijs/joi/security/advisories/GHSA-gg4h-3hg2-grpc",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/hapijs/joi/security/advisories/GHSA-gg4h-3hg2-grpc"
},
{
"name": "https://github.com/hapijs/joi/pull/3134",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/hapijs/joi/pull/3134"
},
{
"name": "https://github.com/hapijs/joi/pull/3135",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/hapijs/joi/pull/3135"
},
{
"name": "https://github.com/hapijs/joi/commit/162f367aa178d2e1ebec8dc1164e5fe16536ddf6",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/hapijs/joi/commit/162f367aa178d2e1ebec8dc1164e5fe16536ddf6"
},
{
"name": "https://github.com/hapijs/joi/commit/172ececa192feda532b743d77bc9d3e523d19b01",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/hapijs/joi/commit/172ececa192feda532b743d77bc9d3e523d19b01"
}
],
"source": {
"advisory": "GHSA-gg4h-3hg2-grpc",
"discovery": "UNKNOWN"
},
"title": "joi: object().rename() with a template target can set the validated object\u0027s prototype"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-84367",
"datePublished": "2026-09-01T20:33:29.295Z",
"dateReserved": "2026-09-01T16:27:58.129Z",
"dateUpdated": "2026-09-01T20:33:29.295Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-84367",
"date": "2026-09-02",
"epss": "0.0027",
"percentile": "0.18815"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-84367\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-09-01T21:18:47.737\",\"lastModified\":\"2026-09-01T21:18:47.737\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"joi is a schema description language and data validator for JavaScript. From 16.0.0 until 17.13.5 and 18.2.4, joi\u0027s 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\u0027s 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.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"hapijs\",\"product\":\"joi\",\"versions\":[{\"version\":\"\u003e= 16.0.0, \u003c 17.13.5\",\"status\":\"affected\"},{\"version\":\"\u003e= 18.0.0, \u003c 18.2.4\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":3.7,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-1321\"}]}],\"references\":[{\"url\":\"https://github.com/hapijs/joi/commit/162f367aa178d2e1ebec8dc1164e5fe16536ddf6\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/hapijs/joi/commit/172ececa192feda532b743d77bc9d3e523d19b01\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/hapijs/joi/pull/3134\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/hapijs/joi/pull/3135\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/hapijs/joi/security/advisories/GHSA-gg4h-3hg2-grpc\",\"source\":\"security-advisories@github.com\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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