FreeBSD : xen-kernel -- x86: Mishandling of instruction pointer truncation during emulation (49211361-ba4d-11e6-ae1b-002590263bf5)

High Nessus Plugin ID 95501


The remote FreeBSD host is missing one or more security-related updates.


The Xen Project reports :

When emulating HVM instructions, Xen uses a small i-cache for fetches from guest memory. The code that handles cache misses does not check if the address from which it fetched lies within the cache before blindly writing to it. As such it is possible for the guest to overwrite hypervisor memory.

It is currently believed that the only way to trigger this bug is to use the way that Xen currently incorrectly wraps CS:IP in 16 bit modes. The included patch prevents such wrapping.

A malicious HVM guest administrator can escalate their privilege to that of the host.


Update the affected packages.

See Also

Plugin Details

Severity: High

ID: 95501

File Name: freebsd_pkg_49211361ba4d11e6ae1b002590263bf5.nasl

Version: $Revision: 3.1 $

Type: local

Published: 2016/12/05

Modified: 2016/12/05

Dependencies: 12634

Risk Information

Risk Factor: High


Base Score: 7.2

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


Base Score: 8.2

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

Vulnerability Information

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

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

Patch Publication Date: 2016/12/04

Vulnerability Publication Date: 2016/09/08

Reference Information

CVE: CVE-2016-7093