SB20260912220 - Reliance on undefined behavior in Linux kernel liveupdate

Description

This security bulletin contains information about 1 vulnerability.

1) Reliance on undefined behavior (CVE-ID: CVE-2026-89568)

CWE-ID: CWE-758 - Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

CVSSv4: 0 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to trigger undefined behavior.

The vulnerability exists due to an incorrect integer shift size calculation in kho_preserved_memory_reserve() when processing properly aligned preservation reservations larger than 2 GiB. A local user can cause an oversized preservation reservation to be processed to trigger undefined behavior.

Such reservations can be obtained through kho_preserve_pages(), including by memblock reserve_mem.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded
• https://git.kernel.org/stable/c/42a6f03cf352eb6e6dbeef95e75e686f4cdb9bd1