Memory safety bugs were reported in Firefox 56 and Firefox ESR 52.4. 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. This vulnerability affects Firefox < 57, Firefox ESR < 52.5, and Thunderbird < 52.5.

Mozilla developers backported selected changes in the Skia library. These changes correct memory corruption issues including invalid buffer reads and writes during graphic operations. This vulnerability affects Thunderbird ESR < 52.8, Thunderbird < 52.8, and Firefox ESR < 52.8.

The Resource Timing API incorrectly revealed navigations in cross-origin iframes. This is a same-origin policy violation and could allow for data theft of URLs loaded by users. This vulnerability affects Firefox < 57, Firefox ESR < 52.5, and Thunderbird < 52.5.

A lack of parameter validation on IPC messages results in a potential out-of-bounds write through malformed IPC messages. This can potentially allow for sandbox escape through memory corruption in the parent process. This vulnerability affects Thunderbird < 52.7, Firefox ESR < 52.7, and Firefox < 59.

A buffer overflow can occur when the image renderer attempts to paint non-displayable SVG elements. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

An out-of-bounds read vulnerability with the Opus encoder when the number of channels in an audio stream changes while the encoder is in use. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

An out-of-bounds read occurs when applying style rules to pseudo-elements, such as ::first-line, using cached style data. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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. This vulnerability affects Thunderbird < 52.6, Firefox ESR < 52.6, and Firefox < 58.

The Pocket toolbar button, once activated, listens for events fired from it's own pages but does not verify the origin of incoming events. This allows content from other origins to fire events and inject content and commands into the Pocket context. Note: this issue does not affect users with e10s enabled. This vulnerability affects Firefox ESR < 45.6 and Firefox < 50.1.

A use-after-free vulnerability can occur in design mode when image objects are resized if objects referenced during the resizing have been freed from memory. This results in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.