The BASH v.<4.3 can be vulnerable. Name: Shellshock.

Some info here:

NIST NVD – Vulnerability Summary for CVE-2014-6271 – https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-6271

Wordfence – http://www.wordfence.com/blog/2014/09/major-bash-vulnerability-disclosed-may-affect-a-large-number-of-websites-and-web-apps/

The Register: http://www.theregister.co.uk/2014/09/24/bash_shell_vuln/

SecurityIntelligence: http://securityintelligence.com/news/shellshock-where-the-bash-bug-could-hit-the-hardest/

CentOS: http://centosnow.blogspot.com/2014/09/critical-bash-updates-for-centos-5.html

ArsTechnica: http://arstechnica.com/security/2014/09/concern-over-bash-vulnerability-grows-as-exploit-reported-in-the-wild/