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

A heap buffer overflow vulnerability may occur in WebAssembly when “shrinkElements” is called followed by garbage collection on memory that is now uninitialized. This results in a potentially exploitable crash. This vulnerability affects Firefox < 58.

A heap buffer overflow vulnerability may occur in WebAssembly during Memory/Table resizing, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 58.

A use-after-free vulnerability can occur when the thread for a Web Worker is freed from memory prematurely instead of from memory in the main thread while cancelling fetch operations. This vulnerability affects Firefox < 58.

A use-after-free vulnerability can occur during WebRTC connections when interacting with the DTMF timers. This results in a potentially exploitable crash. This vulnerability affects Firefox ESR < 52.6 and Firefox < 58.

Memory safety bugs were reported in Firefox 57. 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 < 58.