SB20261022237 - Race condition in Linux kernel s390 kvm

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-98650)

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

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service through kernel crashes.

The vulnerability exists due to a race condition in the Linux kernel's s390 KVM storage-key functions when processing storage-key operations concurrently with large-page splitting. A local user can trigger overlapping operations that cause a page-table entry no longer designating a large page to be used for physical address calculation, leading to kernel crashes.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/27554b9505ddfc0aeab466aeb60929dfa17284c7
• https://git.kernel.org/stable/c/c958f0498891203fddf2764b28f8b102c6bfd719