CVE-2022-49014

A flaw was found in the Linux kernel's net: tun module. A use-after-free vulnerability exists in the tun_detach() function. An attacker with administrative (root) privileges could exploit this by causing a network structure to be prematurely released and then accessed, leading to a system crash (denial of service). This vulnerability could potentially be leveraged for arbitrary code execution.

This issue is considered to be a moderate impact flaw, as the exploitation for this will need an ADMIN (or ROOT) privilege (PR:H) in drivers/net/tun.c.

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 kernel module from loading. This can be achieved by creating a modprobe configuration file.

1. Create or edit /etc/modprobe.d/blacklist-tun.conf and add the following line:

   blacklist tun
   

2. Rebuild the initial ramdisk:

   dracut -f -v
   

3. Reboot the system for the changes to take effect.

Disabling the tun module may impact functionality that relies on virtual network interfaces, such as VPN clients or container networking solutions. A system reboot is required for the changes to take effect.