Amazon Linux AMI Security Advisory: ALAS-2015-476
Advisory Release Date: 2015-02-11 19:48 Pacific
The Linux kernel through 3.17.4 does not properly restrict dropping of supplemental group memberships in certain namespace scenarios, which allows local users to bypass intended file permissions by leveraging a POSIX ACL containing an entry for the group category that is more restrictive than the entry for the other category, aka a "negative groups" issue, related to kernel/groups.c, kernel/uid16.c, and kernel/user_namespace.c. (CVE-2014-8989 )
A flaw was found in the way the Linux kernel's splice() system call validated its parameters. On certain file systems, a local, unprivileged user could use this flaw to write past the maximum file size, and thus crash the system. (CVE-2014-7822 )
Run yum clean all followed by yum update kernel to update your system. You will need to reboot your system in order for the new kernel to be running.