Improper Input Validation
When the Mozilla Updater is run, if the Updater's log file in the working directory points to a hardlink, data can be appended to an arbitrary local file. This vulnerability requires local system access. Note: this issue only affects Windows operating systems. This vulnerability affects Firefox ESR < 45.5 and Firefox < 50.
CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.