CVE-2021-20261

A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver software. The impact of this issue is lessened by the fact that the default permissions on the floppy device (/dev/fd0) are restricted to root. If the permissions on the device have changed the impact changes greatly. In the default configuration root (or equivalent) permissions are required to attack this flaw.

This flaw is rated as having a Moderate impact because the default and supported configuration is not readable by unprivileged users. Moreover, if the attacker is granted access, there are significantly easier attack vectors available.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

As the floppy module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions:

echo "install floppy /bin/true" >> /etc/modprobe.d/disable-floppy.conf

The system will need to be restarted if the floppy modules are loaded and in use.

Alternatively, disabling the floppy in the BIOS or virtual machine configuration and restarting the system will also ensure that the floppy hardware will not autoload the kernel floppy module.

If the system requires this module to work correctly, this mitigation may not be suitable.

If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services.