Still waiting for a fix on Beanstalk. Neither "yum clean all" followed by "yum update bash" nor "yum --releasever=2014.09 update bash" currently work.
EDIT: relevant AWS threads
https://forums.aws.amazon.com/thread.jspa?threadID=161489
https://forums.aws.amazon.com/thread.jspa?threadID=161529&ts...