Debian Security Advisory DSA 3554-1 (xen - security update)

Multiple vulnerabilities have been discovered in the Xen hypervisor. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2016-3158, CVE-2016-3159 (XSA-172) Jan Beulich from SUSE discovered that Xen does not properly handle writes to the hardware FSW.ES bit when running on AMD64 processors. A malicious domain can take advantage of this flaw to obtain address space usage and timing information, about another domain, at a fairly low rate. CVE-2016-3960 (XSA-173) Ling Liu and Yihan Lian of the Cloud Security Team, Qihoo 360 discovered an integer overflow in the x86 shadow pagetable code. A HVM guest using shadow pagetables can cause the host to crash. A PV guest using shadow pagetables (i.e. being migrated) with PV superpages enabled (which is not the default) can crash the host, or corrupt hypervisor memory, potentially leading to privilege escalation.

xen on Debian Linux

This check tests the installed software version using the apt package manager.

For the stable distribution (jessie), these problems have been fixed in version 4.4.1-9+deb8u5. We recommend that you upgrade your xen packages.