Web browsers are used primarily for surfing the Web. However, an outdated web browser can lead to the compromise of the entire system. Clients may never use the preinstalled web browser and choose the one based on their preference. However, the default preinstalled web browser can still lead to various attacks on the system. Exploiting a browser by finding vulnerabilities in the browser components is known as browser-based exploitation.
For more information on Firefox vulnerabilities, refer to http://www.cvedetails.com/product/3264/Mozilla-Firefox.html?vendor_id=452.
For Internet Explorer vulnerabilities, refer to http://www.cvedetails.com/product/9900/Microsoft-Internet-Explorer.html?vendor_id=26.