SB20260912265 - Race condition in Linux kernel include scx

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-89519)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause incorrect task scheduling.

The vulnerability exists due to a race condition in the sched_ext dispatch and task-selection logic when scheduler selections interleave through dispatch lock drops. A local user can trigger interleaved scheduler dispatches and task selections to cause incorrect task scheduling.

A task that has been dequeued can be incorrectly retained as the previous task because a stale runqueue-level decision is consumed by a later selection.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/6f1d3bfe54430f8d54e0530a27f2ecbf8466576e
• https://git.kernel.org/stable/c/ffaab58d217581cb75353168f8812a16e10463fc