CVE-2026-43323

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

sched/fair: Fix zero_vruntime tracking fix

John reported that stress-ng-yield could make his machine unhappy and

managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix

zero_vruntime tracking").

The combination of yield and that commit was specific enough to

hypothesize the following scenario:

Suppose we have 2 runnable tasks, both doing yield. Then one will be

eligible and one will not be, because the average position must be in

between these two entities.

Therefore, the runnable task will be eligible, and be promoted a full

slice (all the tasks do is yield after all). This causes it to jump over

the other task and now the other task is eligible and current is no

longer. So we schedule.

Since we are runnable, there is no {de,en}queue. All we have is the

__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the

fingered commit, those two no longer move zero_vruntime.

All that moves zero_vruntime

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References