A newly disclosed flaw in the Linux kernel's traffic-control subsystem, now assigned CVE-2026-46331 and referred to as “Pedit COW,” .

https://gbhackers.com/critical-linux-kernel-flaw-2/

It has been found to grant any unprivileged local user full root access on vulnerable systems. If an actor can run code inside a vulnerable server, for example through a compromised website, shell account, or application, this bug may allow them to have unrestricted server access.

Mitigations

Where a server is using a modular kernel, you should check with the distributor as soon as possible for updates and additional mitigation steps.

On RimuHosting VPSs, it is possible to disable this attack by setting the following ...

sysctl -w user.max_user_namespaces=0

This temporary fix may have a broader impact, you should test your workloads still operate normally after making this change.

Fixed kernels

We are releasing VM kernels to our hosts with the affected component disabled. For 4.14 and later. A reboot will be required to use those. Please use our kernel selector in our control panel to action that.

• Kernel selection page: https://rimuhosting.com/cp/vps/kernel.jsp

You can verify which kernel your VM is running using the command 'uname -r', it will look something like this...:

6.12.0-really94-rh-20260630114817.xenU.x86_64

Fixed kernels will show a build date of 20260630 or newer. Those digits are the numerical date: 2026 June 30th.

Ongoing work

We are continuing to review this vulnerability, and will be providing updates and further recomendations here. Please subscribe to this notice for updates.