The cramfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems. A cramfs image can be used without having to first decompress the image. Rationale: Removing support for unneeded filesystem types reduces the local attack surface of the system. If this filesystem type is not needed, disable it.
Edit or create a file in the /etc/modprobe.d/ directory ending in .conf with a line that reads install cramfs /bin/false and a line the reads blacklist cramfs. Example: # printf 'install cramfs /bin/false blacklist cramfs ' >> /etc/modprobe.d/cramfs.conf Run the following command to unload the cramfs module: # modprobe -r cramfs