grub2 - security update

Hector Marco and Ismael Ripoll, from Cybersecurity UPV Research Group,
found an integer underflow vulnerability in Grub2, a popular bootloader.
A local attacker can bypass the Grub2 authentication by inserting a
crafted input as username or password.

More information:

http://hmarco.org/bugs/CVE-2015-8370-Grub2-authentication-bypass.html

CVE-2015-8370

For the oldstable distribution (wheezy), this problem has been fixed
in version 1.99-27+deb7u3.

For the stable distribution (jessie), this problem has been fixed in
version 2.02~beta2-22+deb8u1.

For the unstable distribution (sid), this problem has been fixed in
version 2.02~beta2-33.

We recommend that you upgrade your grub2 packages.