xen - several

Several denial-of-service vulnerabilities have been discovered in Xen,
the popular virtualization software. The Common Vulnerabilities and
Exposures project identifies the following issues:

• 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 can be used to crash a client from within, this vulnerability is
  considered to have 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 the host, this vulnerability is
  considered to have 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.