CVE-2025-68231

kernel: mm/mempool: fix poisoning order>0 pages with HIGHMEM

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Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · December 16, 2025

Updated · June 30, 2026

Description

A kernel crash was found in the mempool subsystem of the Linux kernel on systems with CONFIG_HIGHMEM. When poisoning order>0 pages, only the first page is mapped but the code attempts to access the entire high-order page range. This causes page faults on unmapped highmem pages.

Statement

HIGHMEM is a 32-bit x86 feature for accessing memory above ~896MB. Modern 64-bit systems don't use HIGHMEM. This affects 32-bit kernels with large memory configurations using mempool poisoning.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE-805 · Buffer Access with Incorrect Length Value