---
title: "CVE-2016-1836\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-2016-1836?format=md
keywords: index, follow
---

# CVE-2016-1836

Publication date 20 May 2016

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-2016-1836?format=md#impact-score)

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## Description

Use-after-free vulnerability in the xmlDictComputeFastKey function in
libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before
10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote
attackers to cause a denial of service via a crafted XML document.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2016-1836?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| libxml2 | 17.04 zesty | Not affected |
| 16.10 yakkety | Not affected |
| 16.04 LTS xenial | Fixed 2.9.3+dfsg1-1ubuntu0.1 |
| 15.10 wily | Fixed 2.9.2+zdfsg1-4ubuntu0.4 |
| 14.04 LTS trusty | Fixed 2.9.1+dfsg1-3ubuntu4.8 |
| 12.04 LTS precise | Not affected |

---

* [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-2016-1836?format=md#patch-details)

## Notes

---

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

2.9.2 first introduced the flaw but it was backported to Trusty
via 0006-Fix-a-parsing-bug-on-non-ascii-element-and-CR-LF-usa.patch

### 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 |
| --- | --- |
| libxml2 | * Upstream:   [?id=457](https://git.gnome.org/browse/libxml2/commit/?id=45752d2c334b50016666d8f0ec3691e2d680f0a0) |

## 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 | None |
  | User interaction | Required |
  | 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:N/UI:R/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1836)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-1836)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-1836)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-1836)

### Related Ubuntu Security Notices (USN)

+ [USN-2994-1](https://usn.ubuntu.com/USN-2994-1)
+ libxml2 vulnerabilities
+ 6 June 2016

### Other references

* <https://support.apple.com/HT206564>
* <https://support.apple.com/HT206566>
* <https://support.apple.com/HT206567>
* <https://support.apple.com/HT206568>
* <http://lists.apple.com/archives/security-announce/2016/May/msg00001.html>
* <http://lists.apple.com/archives/security-announce/2016/May/msg00002.html>
* <http://lists.apple.com/archives/security-announce/2016/May/msg00003.html>
* <http://lists.apple.com/archives/security-announce/2016/May/msg00004.html>
* <https://www.cve.org/CVERecord?id=CVE-2016-1836>