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Ubuntu Security Notice USN-2723-1
August 27, 2015

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

- Ubuntu 15.04
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

Firefox could be made to crash or run programs as your login if it
opened a malicious website.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

A use-after-free was discovered when resizing a canvas element during
restyling in some circumstances. If a user were tricked in to opening a
specially crafted website, an attacker could potentially exploit this to
cause a denial of service via application crash, or execute arbitrary code
with the privileges of the user invoking Firefox. (CVE-2015-4497)

Bas Venis discovered that the addon install permission prompt could be
bypassed using data: URLs in some circumstances. It was also discovered
that the installation notification could be made to appear over another
site. If a user were tricked in to opening a specially crafted website, an
attacker could potentially exploit this to install a malicious addon.
(CVE-2015-4498)

Update instructions:

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

Ubuntu 15.04:
  firefox                         40.0.3+build1-0ubuntu0.15.04.1

Ubuntu 14.04 LTS:
  firefox                         40.0.3+build1-0ubuntu0.14.04.1

Ubuntu 12.04 LTS:
  firefox                         40.0.3+build1-0ubuntu0.12.04.1

After a standard system update you need to restart Firefox to make
all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-2723-1
  CVE-2015-4497, CVE-2015-4498

Package Information:
  https://launchpad.net/ubuntu/+source/firefox/40.0.3+build1-0ubuntu0.15.04.1
  https://launchpad.net/ubuntu/+source/firefox/40.0.3+build1-0ubuntu0.14.04.1
  https://launchpad.net/ubuntu/+source/firefox/40.0.3+build1-0ubuntu0.12.04.1