The following updates has been released for Ubuntu Linux:

USN-3918-3: Firefox regression
USN-3925-1: FreeImage vulnerability
USN-3927-1: Thunderbird vulnerabilities

USN-3918-3: Firefox regression

==========================================================================
Ubuntu Security Notice USN-3918-3
March 28, 2019

firefox regression
==========================================================================

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

- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

USN-3918-1 caused a regression in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

USN-3918-1 fixed vulnerabilities in Firefox. The update caused web
compatibility issues with some websites. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

 Multiple security issues were discovered in Firefox. If a user were
 tricked in to opening a specially crafted website, an attacker could
 potentially exploit these to cause a denial of service via application
 crash, denial of service via successive FTP authorization prompts or modal
 alerts, trick the user with confusing permission request prompts, obtain
 sensitive information, conduct social engineering attacks, or execute
 arbitrary code. (CVE-2019-9788, CVE-2019-9789, CVE-2019-9790,
 CVE-2019-9791, CVE-2019-9792, CVE-2019-9795, CVE-2019-9796, CVE-2019-9797,
 CVE-2019-9799, CVE-2019-9802, CVE-2019-9805, CVE-2019-9806, CVE-2019-9807,
 CVE-2019-9808, CVE-2019-9809)
 
 A mechanism was discovered that removes some bounds checking for string,
 array, or typed array accesses if Spectre mitigations have been disabled.
 If a user were tricked in to opening a specially crafted website with
 Spectre mitigations disabled, an attacker could potentially exploit this
 to cause a denial of service, or execute arbitrary code. (CVE-2019-9793)
 
 It was discovered that Upgrade-Insecure-Requests was incorrectly enforced
 for same-origin navigation. An attacker could potentially exploit this to
 conduct man-in-the-middle (MITM) attacks. (CVE-2019-9803)

Update instructions:

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

Ubuntu 18.10:
  firefox  66.0.2+build1-0ubuntu0.18.10.1

Ubuntu 18.04 LTS:
  firefox  66.0.2+build1-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
  firefox  66.0.2+build1-0ubuntu0.16.04.1

Ubuntu 14.04 LTS:
  firefox 66.0.2+build1-0ubuntu0.14.04.1

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

References:
  https://usn.ubuntu.com/usn/usn-3918-3
  https://usn.ubuntu.com/usn/usn-3918-1
  https://launchpad.net/bugs/1822185

Package Information:
 
https://launchpad.net/ubuntu/+source/firefox/66.0.2+build1-0ubuntu0.18.10.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.2+build1-0ubuntu0.18.04.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.2+build1-0ubuntu0.16.04.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.2+build1-0ubuntu0.14.04.1

USN-3925-1: FreeImage vulnerability

==========================================================================
Ubuntu Security Notice USN-3925-1
March 28, 2019

freeimage vulnerability
==========================================================================

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

- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

FreeImage could be made to crash or run programs as your login if it
opened a specially crafted file.

Software Description:
- freeimage: Support library for graphics image formats (development files)

Details:

It was discovered that an out-of-bounds write vulnerability existed in the XMP
Image handling functionality of the FreeImage library. If a user or automated
system were tricked into opening a specially crafted image, a remote attacker
could overwrite arbitrary memory, resultin in code execution.

Update instructions:

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

Ubuntu 16.04 LTS:
libfreeimage3 3.17.0+ds1-2ubuntu0.1
libfreeimageplus3 3.17.0+ds1-2ubuntu0.1

Ubuntu 14.04 LTS:
libfreeimage3 3.15.4-3ubuntu0.1

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

References:
https://usn.ubuntu.com/usn/usn-3925-1
CVE-2016-5684

Package Information:
https://launchpad.net/ubuntu/+source/freeimage/3.17.0+ds1-2ubuntu0.1
https://launchpad.net/ubuntu/+source/freeimage/3.15.4-3ubuntu0.1

USN-3927-1: Thunderbird vulnerabilities

==========================================================================
Ubuntu Security Notice USN-3927-1
March 28, 2019

thunderbird vulnerabilities
==========================================================================

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

- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Thunderbird.

Software Description:
- thunderbird: Mozilla Open Source mail and newsgroup client

Details:

It was discovered that Thunderbird allowed PAC files to specify that
requests to localhost are sent through the proxy to another server. If
proxy auto-detection is enabled, an attacker could potentially exploit
this to conduct attacks on local services and tools. (CVE-2018-18506)

Multiple security issues were discovered in Thunderbird. If a user were
tricked in to opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
or execute arbitrary code. (CVE-2019-9788, CVE-2019-9790, CVE-2019-9791,
CVE-2019-9792, CVE-2019-9795, CVE-2019-9796, CVE-2019-9810, CVE-2019-9813)

A mechanism was discovered that removes some bounds checking for string,
array, or typed array accesses if Spectre mitigations have been disabled.
If a user were tricked in to opening a specially crafted website in a
browsing context with Spectre mitigations disabled, an attacker could
potentially exploit this to cause a denial of service, or execute
arbitrary code. (CVE-2019-9793)

Update instructions:

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

Ubuntu 18.10:
  thunderbird  1:60.6.1+build2-0ubuntu0.18.10.1

Ubuntu 18.04 LTS:
  thunderbird  1:60.6.1+build2-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
  thunderbird  1:60.6.1+build2-0ubuntu0.16.04.1

Ubuntu 14.04 LTS:
  thunderbird  1:60.6.1+build2-0ubuntu0.14.04.1

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

References:
  https://usn.ubuntu.com/usn/usn-3927-1
  CVE-2018-18506, CVE-2019-9788, CVE-2019-9790, CVE-2019-9791,
  CVE-2019-9792, CVE-2019-9793, CVE-2019-9795, CVE-2019-9796,
  CVE-2019-9810, CVE-2019-9813

Package Information:
 
https://launchpad.net/ubuntu/+source/thunderbird/1:60.6.1+build2-0ubuntu0.18.10.1
 
https://launchpad.net/ubuntu/+source/thunderbird/1:60.6.1+build2-0ubuntu0.18.04.1
 
https://launchpad.net/ubuntu/+source/thunderbird/1:60.6.1+build2-0ubuntu0.16.04.1
 
https://launchpad.net/ubuntu/+source/thunderbird/1:60.6.1+build2-0ubuntu0.14.04.1