A shared worker created from a "data:" URL in one tab can be shared by another tab with a different origin, bypassing the same-origin policy. This vulnerability affects Firefox < 59.

Memory safety bugs were reported in Firefox ESR 52.6. 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 ESR < 52.7 and Thunderbird < 52.7.

Under certain circumstances the "fetch()" API can return transient local copies of resources that were sent with a "no-store" or "no-cache" cache header instead of downloading a copy from the network as it should. This can result in previously stored, locally cached data of a website being accessible to users if they share a common profile while browsing. This vulnerability affects Firefox ESR < 52.7 and Firefox < 59.

A use-after-free vulnerability can occur when manipulating floating "first-letter" style elements, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 58.

A Blob URL can violate origin attribute segregation, allowing it to be accessed from a private browsing tab and for data to be passed between the private browsing tab and a normal tab. This could allow for the leaking of private information specific to the private browsing context. This issue is mitigated by the requirement that the user enter the Blob URL manually in order for the access violation to occur. This vulnerability affects 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 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. This vulnerability affects Thunderbird < 52.6, Firefox ESR < 52.6, and Firefox < 58.

A potential integer overflow in the "DoCrypt" function of WebCrypto was identified. If a means was found of exploiting it, it could result in an out-of-bounds write. This vulnerability affects Firefox < 58.

The printing process can bypass local access protections to read files available through symlinks, bypassing local file restrictions. The printing process requires files in a specific format so arbitrary data cannot be read but it is possible that some local file information could be exposed. This vulnerability affects Firefox < 58.

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.