The Mozilla Windows updater modifies some files to be updated by reading the original file and applying changes to it. The location of the original file can be altered by a malicious user by passing a special path to the callback parameter through the Mozilla Maintenance Service, allowing the manipulation of files in the installation directory and privilege escalation by manipulating the Mozilla Maintenance Service, which has privileged access. Note: This attack requires local system access and only affects Windows. Other operating systems are not affected. This vulnerability affects Firefox ESR < 52.2 and Firefox < 54.