Fix XSS vulnerability in link regex [Security Issue]

Author: jackycute

public/js/render.js

@@ -3,8 +3,8 @@
 // allow some attributes
 var whiteListAttr = ['id', 'class', 'style']
 window.whiteListAttr = whiteListAttr
-// allow link starts with '.', '/' and custom protocol with '://'
-var linkRegex = /^([\w|-]+:\/\/)|^([.|/])+/
+// allow link starts with '.', '/' and custom protocol with '://', exclude link starts with javascript://
+var linkRegex = /^(?!javascript:\/\/)([\w|-]+:\/\/)|^([.|/])+/
 // allow data uri, from https://gist.github.com/bgrins/6194623
 var dataUriRegex = /^\s*data:([a-z]+\/[a-z0-9-+.]+(;[a-z-]+=[a-z0-9-]+)?)?(;base64)?,([a-z0-9!$&',()*+;=\-._~:@/?%\s]*)\s*$/i
 // custom white list