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Debian Security Advisory DSA-3554-1                   security@debian.org
https://www.debian.org/security/                     Salvatore Bonaccorso
April 21, 2016                        https://www.debian.org/security/faq
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Package        : xen
CVE ID         : CVE-2016-3158 CVE-2016-3159 CVE-2016-3960

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.

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.

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

Mailing list: debian-security-announce@lists.debian.org