Debian: DSA-2531-1 Critical Denial Of Service Threat In Xen

CVE-2012-3432

Guest mode unprivileged code, which has been granted the privilege to
access MMIO regions, may leverage that access to crash the whole guest.
Since this be used to crash a client from within, this vulnerability is
consider with low impact.

CVE-2012-3433

A guest kernel can cause the host to become unresponsive for a period
of time, potentially leading to a DoS. Since an attacker with full
control in the guest can impact on the host, this vulnerability is
consider with high impact.

For the stable distribution (squeeze), this problem has been fixed in
version 4.0.1-5.3.

For the unstable distribution (sid), this problem has been fixed in
version 4.1.3-1.

We recommend that you upgrade your xen packages.

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: http://www.debian.org/security/