CVE-2022-4744

A double-free flaw was found in the Linux kernel’s TUN/TAP device driver functionality in how a user registers the device when the register_netdevice function fails (NETDEV_REGISTER notifier). This flaw allows a local user to crash or potentially escalate their privileges on the system.

Keeping Red Hat Enterprise Linux version 8 with Moderate severity, because required patch 158b515f703e (see reference) missed. However, currently Red Hat Enterprise Linux version 8 not affected, because previous patch not backported too: 766b0515d5be ("net: make sure devices go through netdev_wait_all_refs"). Means that it is not possible to trigger the issue for the Red Hat Enterprise Linux 8, but potentially Red Hat Enterprise Linux version 8 could be vulnerable in future, so still need to fix. For the Red Hat Enterprise Linux version 9 there is known way to reproduce the issue.

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.

To mitigate this issue, prevent the tun module from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.