The kernel packages contain the Linux kernel, the core of any Linux operating system.
These updated packages fix the following security issues:
on AMD64 architectures, the possibility of a kernel crash was discovered by testing the Linux kernel process-trace ability. This could allow a local unprivileged user to cause a denial of service (kernel crash). (CVE-2008-1615, Important)
on 64-bit architectures, the possibility of a timer-expiration value overflow was found in the Linux kernel high-resolution timers functionality, hrtimer. This could allow a local unprivileged user to setup a large interval value, forcing the timer expiry value to become negative, causing a denial of service (kernel hang). (CVE-2007-6712, Important)
the possibility of a kernel crash was found in the Linux kernel IPsec protocol implementation, due to improper handling of fragmented ESP packets. When an attacker controlling an intermediate router fragmented these packets into very small pieces, it would cause a kernel crash on the receiving node during packet reassembly. (CVE-2007-6282, Important)
a potential denial of service attack was discovered in the Linux kernel PWC USB video driver. A local unprivileged user could use this flaw to bring the kernel USB subsystem into the busy-waiting state, causing a denial of service. (CVE-2007-5093, Low)
As well, these updated packages fix the following bugs:
in certain situations, a kernel hang and a possible panic occurred when disabling the cpufreq daemon. This may have prevented system reboots from completing successfully.
continual "softlockup" messages, which occurred on the guest's console after a successful save and restore of a Red Hat Enterprise Linux 5 para-virtualized guest, have been resolved.
in the previous kernel packages, the kernel may not have reclaimed NFS locks after a system reboot.
Red Hat Enterprise Linux 5 users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.