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
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/