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.

If a text string that happens to be a filename in the operating system’s native format is dragged and dropped onto the addressbar the specified local file will be opened. This is contrary to policy and is what would happen if the string were the equivalent “file:” URL. This vulnerability affects Firefox < 60.

If a URL using the “file:” protocol is dragged and dropped onto an open tab that is running in a different child process the tab will open a local file corresponding to the dropped URL, contrary to policy. One way to make the target tab open more reliably in a separate process is to open it with the “noopener” keyword. This vulnerability affects Firefox < 60.

A use-after-free vulnerability can occur during WebGL operations. While this results in a potentially exploitable crash, the vulnerability is limited because the memory is freed and reused in a brief window of time during the freeing of the same callstack. This vulnerability affects Firefox < 60.

A service worker can send the activate event on itself periodically which allows it to run perpetually, allowing it to monitor activity by users. Affects all versions prior to Firefox 60.

A buffer overflow was found during UTF8 to Unicode string conversion within JavaScript with extremely large amounts of data. This vulnerability requires the use of a malicious or vulnerable legacy extension in order to occur. This vulnerability affects Thunderbird ESR < 52.8, Thunderbird < 52.8, and Firefox ESR < 52.8.