CVE-2025-68211

kernel: ksm: use range-walk function to jump over holes in scan_get_next_rmap_item

Loading…

Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · December 16, 2025

Updated · October 29, 2026

Description

A resource exhaustion vulnerability was found in the Kernel Same-page Merging (KSM) subsystem of the Linux kernel. When scanning processes with large sparse virtual memory mappings (e.g., 32 TiB with one mapped page), ksmd inefficiently walks every address rather than skipping unmapped holes. This causes ksmd to consume 100% CPU for extended periods.

Statement

Any process can create large sparse mappings with MADV_MERGEABLE, causing ksmd to waste CPU cycles. This is a denial of service against the KSM deduplication daemon rather than a memory corruption issue.

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-606 · Unchecked Input for Loop Condition