---
id: CVE-2026-93238
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap

  The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap
  on the stack without zero-…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap

  The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap
  on the stack without zero-…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <
    4ba8a08f5f26ed59f356a6318bca3aa7cc0af3e2
  - >-
    Linux >= eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <
    f73db632524320d2b93bc8534be8ea875053502d
  - >-
    Linux >= eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <
    6d554f2571e6b4db242593ba561efd6a6d1f99a9
  - >-
    Linux >= eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <
    09548edc6114f1eb1035b30795e893204ef45b85
  - >-
    Linux >= eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <
    bf09b9d7cd7890bc3a3b7eb63d5ece15f88bfde7
  - Linux 6.0
published: '2026-09-24'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T16:17:19.563'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93238'
references:
  - url: 'https://git.kernel.org/stable/c/09548edc6114f1eb1035b30795e893204ef45b85'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4ba8a08f5f26ed59f356a6318bca3aa7cc0af3e2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6d554f2571e6b4db242593ba561efd6a6d1f99a9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bf09b9d7cd7890bc3a3b7eb63d5ece15f88bfde7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f73db632524320d2b93bc8534be8ea875053502d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T15:45:56.656Z'
---

## Overview

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

s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap

The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap
on the stack without zero-initializing it.

In vfio_ap_mdev_hot_plug_cfg(), the vfio_ap_mdev_filter_matrix() function
is only called to initialize and populate apm_filtered if either
filter_adapters or filter_domains is true. If the hot plug configuration
change only adds control domains (meaning filter_cdoms is true, but
filter_adapters and filter_domains are both false),
vfio_ap_mdev_filter_matrix() is bypassed.

Consequently, apm_filtered is passed to reset_queues_for_apids() with
uninitialized stack garbage. This can cause reset_queues_for_apids() to
interpret arbitrary stack garbage bits as valid APIDs to reset, potentially
performing unintended guest hardware queue resets.

Fix this by zero-initializing the apm_filtered bitmap at the beginning of
vfio_ap_mdev_hot_plug_cfg() using bitmap_zero().

## Remediation

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