Use After Free
A use-after-free vulnerability can occur while editing events in form elements on a page, resulting in a potentially exploitable crash. This vulnerability affects Firefox ESR < 52.6 and Thunderbird < 52.6.
CWE-416 - Use After Free
Use-after-free (UaF) vulnerability occurs when the application is using a pointer to memory that has been freed. Any attempt to read/write to a buffer after it is de-allocated allows memory corruption, sensitive information exposure, and can potentially lead to arbitrary code execution.