---
title: "CVE-2016-9386\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2016-9386?format=md
keywords: index, follow
---

# CVE-2016-9386

Publication date 23 January 2017

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.8 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2016-9386?format=md#impact-score)

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## Description

The x86 emulator in Xen does not properly treat x86 NULL segments as
unusable when accessing memory, which might allow local HVM guest users to
gain privileges via vectors involving "unexpected" base/limit values.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2016-9386?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| xen | 17.04 zesty | Fixed 4.8.0-1ubuntu1 |
| 16.10 yakkety | Fixed 4.7.0-0ubuntu2.1 |
| 16.04 LTS xenial | Fixed 4.6.0-1ubuntu4.3 |
| 14.04 LTS trusty | Fixed 4.4.2-0ubuntu0.14.04.9 |
| 12.04 LTS precise | Fixed 4.1.6.1-0ubuntu0.12.04.13 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

This is XSA-191

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.8 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Local |
  | Attack complexity | Low |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.8 · High |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-9386)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-9386)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-9386)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-9386)

### Other references

* <https://xenbits.xen.org/xsa/advisory-191.html>
* <https://www.cve.org/CVERecord?id=CVE-2016-9386>