When arbitrary text is sent over an FTP connection and a page reload is initiated, it is possible to create a modal alert message with this text as the content. This could potentially be used for social engineering attacks.

If a Sandbox content process is compromised, it can initiate an FTP download which will then use a child process to render the downloaded data. The downloaded data can then be passed to the Chrome process with an arbitrary file length supplied by an attacker, bypassing sandbox protections and allow for a potential memory read of adjacent data from the privileged Chrome process, which may include sensitive data.

Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a "URL Handler" in the Windows registry. Note: This issue only affects Windows operating systems. Other operating systems are unaffected.

Mozilla developers and community members Olli Pettay, Bogdan Tara, Jan de Mooij, Jason Kratzer, Jan Varga, Gary Kwong, Tim Guan-tin Chien, Tyson Smith, Ronald Crane, and Ted Campbell reported memory safety bugs present in Firefox 66 and Firefox ESR 60.6. 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.

Insufficient bounds checking of data during inter-process communication might allow a compromised content process to be able to read memory from the parent process under certain conditions.

On Android systems, Firefox can load a library from APITRACE_LIB, which is writable by all users and applications. This could allow malicious third party applications to execute a man-in-the-middle attack if a malicious code was written to that location and loaded. Note: This issue only affects Android. Other operating systems are unaffected.

Cross-origin images can be read in violation of the same-origin policy by exporting an image after using createImageBitmap to read the image and then rendering the resulting bitmap image within a canvas element.

A use-after-free vulnerability can occur when the SMIL animation controller incorrectly registers with the refresh driver twice when only a single registration is expected. When a registration is later freed with the removal of the animation controller element, the refresh driver incorrectly leaves a dangling pointer to the driver's observer array.

A vulnerability where type-confusion in the IonMonkey just-in-time (JIT) compiler could potentially be used by malicious JavaScript to trigger a potentially exploitable crash.

A vulnerability was discovered where specific command line arguments are not properly discarded during Firefox invocation as a shell handler for URLs. This could be used to retrieve and execute files whose location is supplied through these command line arguments if Firefox is configured as the default URI handler for a given URI scheme in third party applications and these applications insufficiently sanitize URL data. Note: This issue only affects Windows operating systems. Other operating systems are unaffected.