GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables which allows remote attackers to execute arbitrary commands via a crafted environment as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd the mod_cgi and mod_cgid modules in the Apache HTTP Server scripts executed by unspecified DHCP clients and other situations in which setting the environment occurs across a privilege boundary from Bash execution. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271 CVE-2014-7169 and CVE-2014-6277.