---
title: "CVE-2018-15468\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-2018-15468?format=md
keywords: index, follow
---

# CVE-2018-15468

Publication date 17 August 2018

Last updated 26 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**6.0 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2018-15468?format=md#impact-score)

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## Description

An issue was discovered in Xen through 4.11.x. The DEBUGCTL MSR contains
several debugging features, some of which virtualise cleanly, but some do
not. In particular, Branch Trace Store is not virtualised by the processor,
and software has to be careful to configure it suitably not to lock up the
core. As a result, it must only be available to fully trusted guests.
Unfortunately, in the case that vPMU is disabled, all value checking was
skipped, allowing the guest to choose any MSR\_DEBUGCTL setting it likes. A
malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock
up the entire host, causing a Denial of Service.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-15468?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| xen | 26.04 LTS resolute | Not affected |
| 25.10 questing | Not affected |
| 25.04 plucky | Not affected |
| 24.10 oracular | Not affected |
| 24.04 LTS noble | Not affected |
| 23.10 mantic | Not affected |
| 23.04 lunar | Not affected |
| 22.10 kinetic | Not affected |
| 22.04 LTS jammy | Not affected |
| 21.10 impish | Ignored end of life |
| 21.04 hirsute | Ignored end of life |
| 20.10 groovy | Ignored end of life |
| 20.04 LTS focal | Not affected |
| 19.10 eoan | Ignored end of life |
| 19.04 disco | Ignored end of life |
| 18.10 cosmic | Ignored end of life |
| 18.04 LTS bionic | Vulnerable |
| 16.04 LTS xenial | Vulnerable |
| 14.04 LTS trusty | Not in release |

---

* [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)

hypervisor packages are in universe. For
issues in the hypervisor, add appropriate
tags to each section, ex:
Tags\_xen: universe-binary

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

6.0 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.0 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-15468)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-15468)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-15468)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-15468)

### Other references

* <https://xenbits.xen.org/xsa/advisory-269.html>
* <https://www.cve.org/CVERecord?id=CVE-2018-15468>