Updated kernel packages that fix multiple security issues and one bug are now available for Red Hat Enterprise Linux 5.2 Extended Update Support. This update has been rated as having important security impact by the Red Hat Security Response Team.
The kernel packages contain the Linux kernel, the core of any Linux operating system. This update fixes the following security issues: * a system with SELinux enforced was more permissive in allowing local users in the unconfined_t domain to map low memory areas even if the mmap_min_addr restriction was enabled. This could aid in the local exploitation of NULL pointer dereference bugs. (CVE-2009-2695, Important) * a NULL pointer dereference flaw was found in each of the following functions in the Linux kernel: pipe_read_open(), pipe_write_open(), and pipe_rdwr_open(). When the mutex lock is not held, the i_pipe pointer could be released by other processes before it is used to update the pipe's reader and writer counters. This could lead to a local denial of service or privilege escalation. (CVE-2009-3547, Important) This update also fixes the following bug: * a bug in the IPv6 implementation in the Linux kernel could have caused an unbalanced reference count. When using network bonding, this bug may have caused a hang when shutting the system down via "shutdown -h", or prevented the network service from being stopped via "service network stop". (BZ#538409) Users should upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.