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Vulnerability · Published Oct 29, 2026 · Assigned by GitHub_M

CVE-2026-118772joi: quadratic-time split in `string().email({ multiple: true })` allows denial of service

High 7.5

In plain English

A high-severity regular-expression denial of service in joi from @hapi. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 59.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npm@hapi/joino fix listedGHSA-4528-x5fx-h6hg
npmjoi17.13.9GHSA-4528-x5fx-h6hg
npmjoi18.3.1GHSA-4528-x5fx-h6hg

Affected products (as reported)

VendorProductVersions
hapijs joi >= 16.0.0, <= 17.1.1>= 18.0.0, < 18.3.1
@hapi joi >= 16.0.0, <= 17.1.1

Weakness: CWE-1333 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References