—–BEGIN PGP SIGNED MESSAGE—–
Hash: SHA512

– ————————————————————————-
Debian Security Advisory DSA-4112-1 security@debian.org
https://www.debian.org/security/ Moritz Muehlenhoff
February 14, 2018 https://www.debian.org/security/faq
– ————————————————————————-

Package : xen
CVE ID : CVE-2017-17563 CVE-2017-17564 CVE-2017-17565
CVE-2017-17566

Multiple vulnerabilities have been discovered in the Xen hypervisor:

CVE-2017-17563

Jan Beulich discovered that an incorrect reference count overflow
check in x86 shadow mode may result in denial of service or
privilege escalation.

CVE-2017-17564

Jan Beulich discovered that improper x86 shadow mode reference count
error handling may result in denial of service or privilege
escalation.

CVE-2017-17565

Jan Beulich discovered that an incomplete bug check in x86 log-dirty
handling may result in denial of service.

CVE-2017-17566

Jan Beulich discovered that x86 PV guests may gain access to
internally used pages which could result in denial of service or
potential privilege escalation.

In addition this update ships the “Comet” shim to address the Meltdown
class of vulnerabilities for guests with legacy PV kernels. In addition,
the package provides the “Xen PTI stage 1” mitigation which is built-in
and enabled by default on Intel systems, but can be disabled with
`xpti=false’ on the hypervisor command line (It does not make sense to
use both xpti and the Comet shim.)

Please refer to the following URL for more details on how to configure
individual mitigation strategies:
https://xenbits.xen.org/xsa/advisory-254.html

Additional information can also be found in README.pti and README.comet.

For the stable distribution (stretch), these problems have been fixed in
version 4.8.3+comet2+shim4.10.0+comet3-1+deb9u4.1.

We recommend that you upgrade your xen packages.

For the detailed security status of xen please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/xen

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
—–BEGIN PGP SIGNATURE—–
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=o99Q
—–END PGP SIGNATURE—–