Red Hat Product Security has rated this update as having Critical security
impact. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available from the CVE link in the
References section.
The GNU Bourne Again shell (Bash) is a shell and command language
interpreter compatible with the Bourne shell (sh). Bash is the default
shell for Red Hat Enterprise Linux.
A flaw was found in the way Bash evaluated certain specially crafted
environment variables. An attacker could use this flaw to override or
bypass environment restrictions to execute shell commands. Certain
services and applications allow remote unauthenticated attackers to
provide environment variables, allowing them to exploit this issue.