The remote Scientific Linux host is missing one or more security
The kernel packages contain the Linux kernel, the core of any Linux
This update fixes the following security issues :
- It was found that the Xen hypervisor implementation as
shipped with Scientific Linux 5 did not properly
restrict the syscall return addresses in the sysret
return path to canonical addresses. An unprivileged user
in a 64-bit para-virtualized guest, that is running on a
64-bit host that has an Intel CPU, could use this flaw
to crash the host or, potentially, escalate their
privileges, allowing them to execute arbitrary code at
the hypervisor level. (CVE-2012-0217, Important)
- It was found that guests could trigger a bug in earlier
AMD CPUs, leading to a CPU hard lockup, when running on
the Xen hypervisor implementation. An unprivileged user
in a 64-bit para-virtualized guest could use this flaw
to crash the host. Warning: After installing this
update, hosts that are using an affected AMD CPU (refer
to upstream bug #824966 for a list) will fail to boot.
In order to boot such hosts, the new kernel parameter,
allow_unsafe, can be used ('allow_unsafe=on'). This
option should only be used with hosts that are running
trusted guests, as setting it to 'on' reintroduces the
flaw (allowing guests to crash the host).
Note: For Scientific Linux guests, only privileged guest users can
exploit the CVE-2012-0217 and CVE-2012-2934 issues.
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.
See also :
Update the affected packages.
Risk factor :
High / CVSS Base Score : 7.2
Public Exploit Available : true