xen-tools -- delimiter injection vulnerabilities in pygrub

The Xen Project reports:

pygrub, the boot loader emulator, fails to quote (or sanity check) its results when reporting them to its caller.

A malicious guest administrator can obtain the contents of sensitive host files (an information leak). Additionally, a malicious guest administrator can cause files on the host to be removed, causing a denial of service. In some unusual host configurations, ability to remove certain files may be usable for privilege escalation.

[source]