thunderbird: multiple issues

• CVE-2015-2724, CVE-2015-2725, CVE-2015-2726 (Miscellaneous memory
  safety hazards):

Mozilla developers and community identified and fixed several memory
safety bugs in the browser engine used in Firefox and other
Mozilla-based products. Some of these bugs showed evidence of memory
corruption under certain circumstances, and we presume that with enough
effort at least some of these could be exploited to run arbitrary code.
In general these flaws cannot be exploited through email in the
Thunderbird product because scripting is disabled, but are potentially a
risk in browser or browser-like contexts.

• CVE-2015-2731 (Use-after-free in Content Policy due to microtask
  execution error):

Security researcher Herre reported a use-after-free vulnerability when a
Content Policy modifies the Document Object Model to remove a DOM
object, which is then used afterwards due to an error in microtask
implementation. This leads to an exploitable crash.
In general this flaw cannot be exploited through email in the
Thunderbird product because scripting is disabled, but is potentially a
risk in browser or browser-like contexts.

• CVE-2015-2734, CVE-2015-2735, CVE-2015-2736, CVE-2015-2737,
  CVE-2015-2738, CVE-2015-2739, CVE-2015-2740 (Vulnerabilities found
  through code inspection):

Security researcher Ronald Crane reported seven vulnerabilities
affecting released code that he found through code inspection. These
included three uses of uninitialized memory, one poor validation leading
to an exploitable crash, one read of unowned memory in zip files, and
two buffer overflows. These do not all have clear mechanisms to be
exploited through web content but are vulnerable if a mechanism can be
found to trigger them.

• CVE-2015-2741 (Key pinning is ignored when overridable errors are
  encountered):

Mozilla security engineer David Keeler reported that when an overridable
error is encountered, such as those for expired certificates or a host
name does not match a certificate, pinning checks can be be skipped.
This would allow for a user to override a pinned certificate when they
should not be able to do so. This issue does not allow for third parties
to cause a certificate to be overridden and the user would still have to
manually do so.
In general this flaw cannot be exploited through email in the
Thunderbird product because scripting is disabled, but is potentially a
risk in browser or browser-like contexts.