Related Vulnerabilities: CVE-2022-1966  

A use-after-free vulnerability was found in the Linux kernel's Netfilter subsystem in net/netfilter/nf_tables_api.c. This flaw allows a local attacker with user access to cause a privilege escalation issue.

Description

A use-after-free vulnerability was found in the Linux kernel's Netfilter subsystem in net/netfilter/nf_tables_api.c. This flaw allows a local attacker with user access to cause a privilege escalation issue.

Mitigation

In order 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.

Additional Information

  • Bugzilla 2092427: CVE-2022-1966 kernel: a use-after-free write in the netfilter subsystem can lead to privilege escalation to root
  • CWE-416: Use After Free
  • FAQ: Frequently asked questions about CVE-2022-1966