CVE-2016-0634 Red Hat Update for bash Security (RHSA-2017:0725)

The bash packages provide Bash (Bourne-again shell), which is the default shell for Red Hat Enterprise Linux.

An arbitrary command injection flaw was found in the way bash processed the hostname value. A malicious DHCP server could use this flaw to execute arbitrary commands on the DHCP client machines running bash under specific circumstances. (CVE-2016-0634)
An arbitrary command injection flaw was found in the way bash processed the SHELLOPTS and PS4 environment variables. A local, authenticated attacker could use this flaw to exploit poorly written setuid programs to elevate their privileges under certain circumstances. (CVE-2016-7543)
A denial of service flaw was found in the way bash handled popd commands. A poorly written shell script could cause bash to crash resulting in a local denial of service limited to a specific bash session. (CVE-2016-9401)

A malicious DHCP server could use this flaw to execute arbitrary commands on the DHCP client machines running bash under specific circumstances. (CVE-2016-0634)
A local, authenticated attacker could use this flaw to exploit poorly written setuid programs to elevate their privileges under certain circumstances. (CVE-2016-7543)
A poorly written shell script could cause bash to crash resulting in a local denial of service limited to a specific bash session. (CVE-2016-9401)

Upgrade to the latest packages which contain a patch. Refer to Applying Package Updates to RHEL system for details.

Refer to Red Hat security advisory RHSA-2017:0725 to address this issue and obtain more information.

Patch:
Following are links for downloading patches to fix the vulnerabilities:

RHSA-2017:0725: Red Hat Enterprise Linux