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[ CVE-2026-118772 · Published 29 Oct 2026 ]

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

CVSS 7.5 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]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.

[ Fixes ]Fixes and patches

  • joi 17.13.9Fixed version · GitHub Advisories · npm package joi: upgrade to 17.13.9 or later (affected >= 17.1.1, < 17.13.9)
  • joi 18.3.1Fixed version · GitHub Advisories · npm package joi: upgrade to 18.3.1 or later (affected >= 18.0.0, < 18.3.1)

[ Packages ]Affected open-source packages

[ References ]References