joi is a schema description language and data validator for JavaScript. From 17.1.1 until 17.13.9 and 18.3.1, the Joi.string().email({ multiple: true }) rule uses a separator regular expression whose leading whitespace quantifier is retried at every position in a long whitespace run that contains no separator, causing quadratic work during String.prototype.split. The behavior applies to the default separator and every custom separator. Applications that validate attacker-controlled values with the multiple option and no effective prior length limit can have the Node.js event loop blocked for seconds by one request, preventing other work. A .max() rule is not sufficient when abortEarly: false allows the email rule to run after the maximum-length check fails. This vulnerability is fixed in versions 17.13.9 and 18.3.1.

Project Subscriptions

Vendors Products
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-4528-x5fx-h6hg joi: quadratic-time split in `string().email({ multiple: true })` allows denial of service
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 30 Oct 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Hapijs
Hapijs joi
Vendors & Products Hapijs
Hapijs joi

Fri, 30 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 29 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Description joi is a schema description language and data validator for JavaScript. From 17.1.1 until 17.13.9 and 18.3.1, the Joi.string().email({ multiple: true }) rule uses a separator regular expression whose leading whitespace quantifier is retried at every position in a long whitespace run that contains no separator, causing quadratic work during String.prototype.split. The behavior applies to the default separator and every custom separator. Applications that validate attacker-controlled values with the multiple option and no effective prior length limit can have the Node.js event loop blocked for seconds by one request, preventing other work. A .max() rule is not sufficient when abortEarly: false allows the email rule to run after the maximum-length check fails. This vulnerability is fixed in versions 17.13.9 and 18.3.1.
Title joi: quadratic-time split in `string().email({ multiple: true })` allows denial of service
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-29T18:13:33.771Z

Reserved: 2026-10-28T19:20:05.018Z

Link: CVE-2026-118772

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-29T19:17:19.563

Modified: 2026-10-30T19:37:07.073

Link: CVE-2026-118772

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-29T18:13:33Z

Links: CVE-2026-118772 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T22:30:13Z

Weaknesses