Security vulnerabilities fixed in Thunderbird 45.5 — Mozilla

A heap-buffer-overflow in Cairo when processing SVG content caused by compiler optimization, resulting in a potentially exploitable crash.
The Mozilla Updater can be made to choose an arbitrary target working directory for output files resulting from the update process. This vulnerability requires local system access. Note: this issue only affects Windows operating systems.
An error in argument length checking in JavaScript, leading to potential integer overflows or other bounds checking issues.
A buffer overflow resulting in a potentially exploitable crash due to memory allocation issues when handling large amounts of incoming data.
A same-origin policy bypass with local shortcut files to load arbitrary local content from disk.
An existing mitigation of timing side-channel attacks is insufficient in some circumstances. This issue is addressed in Network Security Services (NSS) 3.26.1.
Mozilla developers and community members Olli Pettay, Christian Holler, Ehsan Akhgari, Jon Coppeard, Gary Kwong, Tooru Fujisawa, Philipp, and Randell Jesup reported memory safety bugs present in Thunderbird ESR 45.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code.