Reliance on undefined behavior in Linux kernel - CVE-2026-89568
Published: September 12, 2026
Vulnerability identifier: #VU149242
CSH Severity: Low
CVSS v4: 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]
CVE-ID: CVE-2026-89568
CWE-ID: CWE-758
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-89568
Install security update from vendor's repository.