The remote Debian host is missing a security-related update.
Jann Horn discovered that FUSE, a Filesystem in USErspace, allows the bypass of the 'user_allow_other' restriction when SELinux is active (including in permissive mode). A local user can take advantage of this flaw in the fusermount utility to bypass the system configuration and mount a FUSE filesystem with the 'allow_other' mount option.
Upgrade the fuse packages. For the stable distribution (stretch), this problem has been fixed in version 2.9.7-1+deb9u1.