CVE-2026-118772
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
In joi 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. This 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.
Risk Assessment
An attacker can send a single request with a long whitespace run to block the Node.js event loop for seconds and prevent handling of other operations. This results in denial of service in applications validating untrusted email addresses with the multiple option.
Recommendation
Update joi to version 17.13.9 or 18.3.1 (or later). Additionally enforce an effective length limit on validated values before the email rule, noting that .max() may not suffice with abortEarly: false.
Other vulnerabilities in joi
See all- CVE-2026-92599High
joi (npm package `joi`, hapi.js) versions >=17.2.0 <17.13.7 and >=18.0.0 <18.2.6 are vulnerable to regular expression denial of service in the `Joi.string().isoDate()` validation rule. One of the regular expressions the rule applies to the input is unanchored, so a valid ISO date followed by a long run of fractional-second digits causes the regex engine to restart its search from every position in the string, yielding time proportional to the square of the input length (about 1.4 s for 64 KB of digits and about 22 s for 256 KB). A remote attacker who can supply a string to an isoDate validation can stall the application with a single request. Fixed in 17.13.7 and 18.2.6; as a workaround, cap the length of the string before it reaches joi.
- CVE-2026-90771Low
joi before versions 17.13.8 and 18.2.9 contains a prototype pollution vulnerability in the messages compilation function that accepts __proto__ as an error code. Attackers can supply __proto__ keys in custom messages to replace the returned object's prototype, breaking downstream code relying on Object.prototype methods.
- CVE-2026-84368Low
The joi library (and @hapi/joi) has a prototype pollution vulnerability in lib/messages.js. The exports.compile() and exports.merge() functions reuse inherited objects for attacker-controlled language keys, allowing properties to be written to Object.prototype.
- CVE-2026-84367Low
In the joi library, there is a vulnerability in the internals.rename() implementation used by object().rename(). It allows creating a schema that, using a regular expression and a Joi.expression() or Joi.x() target with match data interpolation, can set the prototype of the object returned by validate() to __proto__ instead of creating an own key.
- CVE-2026-48038Medium
A vulnerability in the joi library (versions before 17.13.4 and 18.2.1) allows a DoS attack by sending deeply nested JSON or objects with recursive link() schemas. Calling validate() without try/catch in a request handler can cause an unhandled RangeError and potentially crash the process.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS