Ubuntu Security Notice USN-3235-1

16th March, 2017

libxml2 vulnerabilities

A security issue affects these releases of Ubuntu and its
derivatives:

• Ubuntu 16.10
• Ubuntu 16.04 LTS
• Ubuntu 14.04 LTS
• Ubuntu 12.04 LTS

Summary

Several security issues were fixed in libxml2.

Software description

• libxml2
  – GNOME XML library

Details

It was discovered that libxml2 incorrectly handled format strings. If a
user or automated system were tricked into opening a specially crafted
document, an attacker could possibly cause libxml2 to crash, resulting in a
denial of service. This issue only affected Ubuntu 12.04 LTS, Ubuntu 14.04
LTS, and Ubuntu 16.04 LTS. (CVE-2016-4448)

It was discovered that libxml2 incorrectly handled certain malformed
documents. If a user or automated system were tricked into opening a
specially crafted document, an attacker could cause libxml2 to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2016-4658)

Nick Wellnhofer discovered that libxml2 incorrectly handled certain
malformed documents. If a user or automated system were tricked into
opening a specially crafted document, an attacker could cause libxml2 to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2016-5131)

Update instructions

The problem can be corrected by updating your system to the following
package version:

Ubuntu 16.10:

libxml2

2.9.4+dfsg1-2ubuntu0.1

Ubuntu 16.04 LTS:

libxml2

2.9.3+dfsg1-1ubuntu0.2

Ubuntu 14.04 LTS:

libxml2

2.9.1+dfsg1-3ubuntu4.9

Ubuntu 12.04 LTS:

libxml2

2.7.8.dfsg-5.1ubuntu4.17

To update your system, please follow these instructions:
https://wiki.ubuntu.com/Security/Upgrades.

After a standard system update you need to reboot your computer to make
all the necessary changes.

References

CVE-2016-4448,

CVE-2016-4658,

CVE-2016-5131