The kernel packages contain the Linux kernel, the core of any Linux operating system.
A flaw was found in the kernel's implementation of the Berkeley Packet Filter (BPF). A local attacker could craft BPF code to crash the system by creating a situation in which the JIT compiler would fail to correctly optimize the JIT image on the last pass. This would lead to the CPU executing instructions that were not part of the JIT code. (CVE-2015-4700, Important)
Two flaws were found in the way the Linux kernel's networking implementation handled UDP packets with incorrect checksum values. A remote attacker could potentially use these flaws to trigger an infinite loop in the kernel, resulting in a denial of service on the system, or cause a denial of service in applications using the edge triggered epoll functionality. (CVE-2015-5364, CVE-2015-5366, Important)
A flaw was found in the way the Linux kernel's ext4 file system handled the "page size > block size" condition when the fallocate zero range functionality was used. A local attacker could use this flaw to crash the system. (CVE-2015-0275, Moderate)
It was found that the Linux kernel's keyring implementation would leak memory when adding a key to a keyring via the add_key() function. A local attacker could use this flaw to exhaust all available memory on the system. (CVE-2015-1333, Moderate)
A race condition flaw was found in the way the Linux kernel's SCTP implementation handled Address Configuration lists when performing Address Configuration Change (ASCONF). A local attacker could use this flaw to crash the system via a race condition triggered by setting certain ASCONF options on a socket. (CVE-2015-3212, Moderate)
An information leak flaw was found in the way the Linux kernel's Virtual Dynamic Shared Object (vDSO) implementation performed address randomization. A local, unprivileged user could use this flaw to leak kernel memory addresses to user-space. (CVE-2014-9585, Low)
Red Hat would like to thank Daniel Borkmann for reporting CVE-2015-4700, and Canonical for reporting the CVE-2015-1333 issue. The CVE-2015-0275 issue was discovered by Xiong Zhou of Red Hat, and the CVE-2015-3212 issue was discovered by Ji Jianwen of Red Hat Engineering.
This update also fixes several bugs. Refer to the following Knowledgebase article for further information:
All kernel users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.