A privilege escalation vulnerability in FortiClient for Linux 6.2.1 and below may allow a user with low privilege to overwrite system files as root with arbitrary content through system backup file via specially crafted "BackupConfig" type IPC client requests to the fctsched process. Further more, FortiClient for Linux 6.2.2 and below allow low privilege user write the system backup file under root privilege through GUI thus can cause root system file overwrite.