==========================================================================
Ubuntu Security Notice USN-3271-1
April 28, 2017

libxslt vulnerabilities
==========================================================================

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

- Ubuntu 17.04
- Ubuntu 16.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in Libxslt.

Software Description:
- libxslt: XSLT processing library

Details:

Holger Fuhrmannek discovered an integer overflow in the
xsltAddTextString() function in Libxslt. An attacker could use
this to craft a malicious document that, when opened, could cause a
denial of service (application crash) or possible execute arbitrary
code. (CVE-2017-5029)

Nicolas Gregoire discovered that Libxslt mishandled namespace
nodes. An attacker could use this to craft a malicious document that,
when opened, could cause a denial of service (application crash)
or possibly execute arbtrary code. This issue only affected Ubuntu
16.04 LTS, Ubuntu 14.04 LTS, and Ubuntu 12.04 LTS. (CVE-2016-1683)

Sebastian Apelt discovered that a use-after-error existed in the
xsltDocumentFunctionLoadDocument() function in Libxslt. An attacker
could use this to craft a malicious document that, when opened,
could cause a denial of service (application crash) or possibly
execute arbitrary code. This issue only affected Ubuntu 16.04 LTS,
Ubuntu 14.04 LTS, and Ubuntu 12.04 LTS. (CVE-2016-1841)

It was discovered that a type confusion error existed in the
xsltStylePreCompute() function in Libxslt. An attacker could use this
to craft a malicious XML file that, when opened, caused a denial of
service (application crash). This issue only affected Ubuntu 14.04
LTS and Ubuntu 12.04 LTS. (CVE-2015-7995)

Nicolas Gregoire discovered the Libxslt mishandled the 'i' and 'a'
format tokens for xsl:number data. An attacker could use this to
craft a malicious document that, when opened, could cause a denial of
service (application crash). This issue only affected Ubuntu 16.04 LTS,
Ubuntu 14.04 LTS, and Ubuntu 12.04 LTS. (CVE-2016-1684)

It was discovered that the xsltFormatNumberConversion() function
in Libxslt did not properly handle empty decimal separators. An
attacker could use this to craft a malicious document that, when
opened, could cause a denial of service (application crash). This
issue only affected Ubuntu 16.10, Ubuntu 16.04 LTS, Ubuntu 14.04 LTS,
and Ubuntu 12.04 LTS. (CVE-2016-4738)

Update instructions:

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

Ubuntu 17.04:
  libxslt1.1                      1.1.29-2ubuntu0.1

Ubuntu 16.10:
  libxslt1.1                      1.1.29-1ubuntu0.1

Ubuntu 16.04 LTS:
  libxslt1.1                      1.1.28-2.1ubuntu0.1

Ubuntu 14.04 LTS:
  libxslt1.1                      1.1.28-2ubuntu0.1

Ubuntu 12.04 LTS:
  libxslt1.1                      1.1.26-8ubuntu1.4

In general, a standard system update will make all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-3271-1
  CVE-2015-7995, CVE-2016-1683, CVE-2016-1684, CVE-2016-1841,
  CVE-2016-4738, CVE-2017-5029

Package Information:
  https://launchpad.net/ubuntu/+source/libxslt/1.1.29-2ubuntu0.1
  https://launchpad.net/ubuntu/+source/libxslt/1.1.29-1ubuntu0.1
  https://launchpad.net/ubuntu/+source/libxslt/1.1.28-2.1ubuntu0.1
  https://launchpad.net/ubuntu/+source/libxslt/1.1.28-2ubuntu0.1
  https://launchpad.net/ubuntu/+source/libxslt/1.1.26-8ubuntu1.4