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FreeBSD : xen-kernel -- x86 segment base write emulation lacking canonical address checks (53dbd096-ba4d-11e6-ae1b-002590263bf5)

medium Nessus Plugin ID 95507

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Synopsis

The remote FreeBSD host is missing a security-related update.

Description

The Xen Project reports :

Both writes to the FS and GS register base MSRs as well as the WRFSBASE and WRGSBASE instructions require their input values to be canonical, or a #GP fault will be raised. When the use of those instructions by the hypervisor was enabled, the previous guard against #GP faults (having recovery code attached) was accidentally removed.

A malicious guest administrator can crash the host, leading to a DoS.

Solution

Update the affected package.

See Also

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214936

https://xenbits.xen.org/xsa/advisory-193.html

http://www.nessus.org/u?ccedfeff

Plugin Details

Severity: Medium

ID: 95507

File Name: freebsd_pkg_53dbd096ba4d11e6ae1b002590263bf5.nasl

Version: 3.9

Type: local

Published: 12/5/2016

Updated: 1/15/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2016-9385

CVSS v3

Risk Factor: Medium

Base Score: 6

Temporal Score: 5.2

Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:xen-kernel

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 12/4/2016

Vulnerability Publication Date: 11/22/2016

Reference Information

CVE: CVE-2016-9385