Security vulnerabilities fixed in Thunderbird 52.6 — Mozilla

An integer overflow vulnerability in the Skia library when allocating memory for edge builders on some systems with at least 8 GB of RAM. This results in the use of uninitialized memory, resulting in a potentially exploitable crash.
A use-after-free vulnerability can occur while editing events in form elements on a page, resulting in a potentially exploitable crash.
A use-after-free vulnerability can occur during XSL transformations when the source document for the transformation is manipulated by script content during the transformation. This results in a potentially exploitable crash.
A use-after-free vulnerability can occur when form input elements, focus, and selections are manipulated by script content. This results in a potentially exploitable crash.
A use-after-free vulnerability can occur when the widget listener is holding strong references to browser objects that have previously been freed, resulting in a potentially exploitable crash when these references are used.
A use-after-free vulnerability can occur when manipulating HTML media elements with media streams, resulting in a potentially exploitable crash.
A use-after-free vulnerability can occur during mouse event handling due to issues with multiprocess support. This results in a potentially exploitable crash.
A use-after-free vulnerability can occur during font face manipulation when a font face is freed while still in use, resulting in a potentially exploitable crash.
If right-to-left text is used in the addressbar with left-to-right alignment, it is possible in some circumstances to scroll this text to spoof the displayed URL. This issue could result in the wrong URL being displayed as a location, which can mislead users to believe they are on a different site than the one loaded.
Mozilla developers and community members Christian Holler, Jason Kratzer, Marcia Knous, Nathan Froyd, Oriol Brufau, Ronald Crane, Randell Jesup, Tyson Smith, Emilio Cobos Álvarez, Ryan VanderMeulen, Sebastian Hengst, Karl Tomlinson, Xidorn Quan, Ludovic Hirlimann, and Jason Orendorff reported memory safety bugs present in Firefox 57, Firefox ESR 52.5, and Thunderbird 52.5. 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.