In FreeBSD 12.2-STABLE before r365772, 11.4-STABLE before r365773, 12.1-RELEASE before p10, 11.4-RELEASE before p4 and 11.3-RELEASE before p14 a ftpd(8) bug in the implementation of the file system sandbox, combined with capabilities available to an authenticated FTP user, can be used to escape the file system restriction configured in ftpchroot(5). Moreover, the bug allows a malicious client to gain root privileges.
建议您更新当前系统或软件至最新版,完成漏洞的修复。