---
title: "CVE-2018-15859\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-2018-15859?format=md
keywords: index, follow
---

# CVE-2018-15859

Publication date 25 August 2018

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.5 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2018-15859?format=md#impact-score)

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## Description

Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs
in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local
attackers to crash (NULL pointer dereference) the xkbcommon parser by
supplying a crafted keymap file, because lookup failures are mishandled.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| libxkbcommon | 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Fixed 0.8.0-1ubuntu0.1 |
| 16.04 LTS xenial | Fixed 0.5.0-1ubuntu2.1 |
| 14.04 LTS trusty | Fixed 0.4.1-0ubuntu1.1 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2018-15859?format=md#patch-details)

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| libxkbcommon | * Vendor:   [bb4909d](https://github.com/xkbcommon/libxkbcommon/commit/bb4909d2d8fa6b08155e449986a478101e2b2634) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.5 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.5 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-15859)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-15859)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-15859)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-15859)

### Related Ubuntu Security Notices (USN)

+ [USN-3786-1](https://usn.ubuntu.com/USN-3786-1)
+ libxkbcommon vulnerabilities
+ 8 October 2018

+ [USN-3786-2](https://usn.ubuntu.com/USN-3786-2)
+ libxkbcommon vulnerabilities
+ 6 November 2018

### Other references

* <https://lists.freedesktop.org/archives/wayland-devel/2018-August/039243.html>
* <https://www.cve.org/CVERecord?id=CVE-2018-15859>