Incomplete Filtering of One or More Instances of Special Elements Affecting org.webjars.npm:validator package, versions [,13.15.22)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-ORGWEBJARSNPM-14152011
- published1 Dec 2025
- disclosed18 Oct 2025
- creditKarol Wrótniak
Introduced: 18 Oct 2025
CVE-2025-12758 (opens in a new tab)How to fix?
Upgrade org.webjars.npm:validator to version 13.15.22 or higher.
Overview
org.webjars.npm:validator is an A library of string validators and sanitizers.
Affected versions of this package are vulnerable to Incomplete Filtering of One or More Instances of Special Elements in the isLength() function that does not take into account Unicode variation selectors (\uFE0F, \uFE0E) appearing in a sequence which lead to improper string length calculation. This can lead to an application using isLength for input validation accepting strings significantly longer than intended, resulting in issues like data truncation in databases, buffer overflows in other system components, or denial-of-service.
PoC
Input;
const validator = require('validator');
console.log(Is "test" (String.length: ${'test'.length}) length less than or equal to 3? ${validator.isLength('test', { max: 3 })}); console.log(Is "test" (String.length: ${'test'.length}) length less than or equal to 4? ${validator.isLength('test', { max: 4 })}); console.log(Is "test\uFE0F\uFE0F\uFE0F\uFE0F" (String.length: ${'test\uFE0F\uFE0F\uFE0F\uFE0F'.length}) length less than or equal to 4? ${validator.isLength('test\uFE0F\uFE0F\uFE0F', { max: 4 })});
Output:
Is "test" (String.length: 4) length less than or equal to 3? false
Is "test" (String.length: 4) length less than or equal to 4? true
Is "test️️️️" (String.length: 8) length less than or equal to 4? true