CVE-2020-5299: Potential CSV Injection vector in OctoberCMS

In OctoberCMS (october/october composer package) versions from 1.0.319 and before 1.0.466, any users with the ability to modify any data that could eventually be exported as a CSV file from the ImportExportController could potentially introduce a CSV injection into the data to cause the generated CSV export file to be malicious. This requires attackers to achieve the following before a successful attack can be completed: 1. Have found a vulnerability in the victims spreadsheet software of choice. 2. Control data that would potentially be exported through the ImportExportController by a theoretical victim. 3. Convince the victim to export above data as a CSV and run it in vulnerable spreadsheet software while also bypassing any sanity checks by said software. Issue has been patched in Build 466 (v1.0.466).