---
id: CVE-2026-98262
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY

  A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for
  JMicron JMB582/JMB585") made …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY

  A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for
  JMicron JMB582/JMB585") made …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    0191c9ff23ef1678dbfb5ad253a2dee92feb5d71
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    8f510f68208a1f673d7c7234a687be4671490e9c
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    4719424bb7cb9f20b73986bcb72dd528f0e5c6eb
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    a5a8b4737f68bbac8aa0685af0c8921e6003c22b
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    b28a17d4a9bb0aa38b48681c3927b012ba40eabe
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    b691a3e244278362e552439d6d3ee5a5d3703488
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    7912ad8fb5233bb8cfe21d50df639c7f4854ff9d
  - >-
    Linux >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c <
    82e47533221d4746947b74d2e79a478c36c6433a
  - Linux 2.6.22
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:18:15.347'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98262'
references:
  - url: 'https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.427Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY

A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for
JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board.

The failure is seen as soon as the ahci driver is probed, and booting with
iommu=off does not solve the problem.

Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0'
for HBAs that do not support 64-bit addressing.

For HBAs that do support 64-bit addressing, the registers are read write,
with a reset value that is Implementation Specific.

When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit
addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64.
Thus, in this case, we need to explicitly clear the registers to 0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.