CVE-2019-18178

Real Time Engineers FreeRTOS+FAT 160919a has a use after free. The function FF_Close() is defined in ff_file.c. The file handler pxFile is freed by ffconfigFREE, which (by default) is a macro definition of vPortFree(), but it is reused to flush modified file content from the cache to disk by the function FF_FlushCache().