CVE-2023-6622

A null pointer dereference vulnerability was found in nft_dynset_init() in net/netfilter/nft_dynset.c in nf_tables in the Linux kernel. This issue may allow a local attacker with CAP_NET_ADMIN user privilege to trigger a denial of service.

To trigger the issue, it requires the ability to create user/net namespaces.

On non-containerized deployments of Red Hat Enterprise Linux 8, you can disable user namespaces by setting user.max_user_namespaces to 0:

echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf
sysctl -p /etc/sysctl.d/userns.conf

On containerized deployments, such as Red Hat OpenShift Container Platform, do not use this mitigation, as the functionality is needed to be enabled.

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.

Mitigation for this issue is to skip loading the affected module "netfilter" onto the system till we have a fix available, this can be done by a blacklist mechanism, this will ensure the driver is not loaded at the boot time.

How do I blacklist a kernel module to prevent it from loading automatically?
https://access.redhat.com/solutions/41278