It’s finals season across many U.S. schools and universities, but for some students and teachers, the already stressful period has been aggravated by a cyberattack on a widely-used learning system that could put at risk the personal information of millions of its users. Multiple schools have reported that Canvas, a web-based platform by ed-tech firm Instructure that is used for course content, assignments, and grades , went offline on Thursday. According to Instructure, Canvas has more than 30