CVE-2026-93238

Guest queue resets via uninitialized APID bitmap

Published Sep 24, 2026 · Updated Sep 24, 2026

Improper initialization in Linux 6.0 allows local users to reset unintended guest hardware queues during s390 AP hot-plug. In vfio_ap_mdev_hot_plug_cfg(), a control-domain-only change bypasses vfio_ap_mdev_filter_matrix(), leaving apm_filtered uninitialized before reset_queues_for_apids() consumes it. Reaching the flaw requires administrative reconfiguration of vfio-ap on an IBM Z host with AP hardware and an attached KVM guest; the bounded consequence is unintended guest queue resets.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in Linux 6.0 allows local users to reset unintended guest hardware queues during s390 AP hot-plug. In vfio_ap_mdev_hot_plug_cfg(), a control-domain-only change bypasses vfio_ap_mdev_filter_matrix(), leaving apm_filtered uninitialized before reset_queues_for_apids() consumes it. Reaching the flaw requires administrative reconfiguration of vfio-ap on an IBM Z host with AP hardware and an attached KVM guest; the bounded consequence is unintended guest queue resets.

The record

CVE
CVE-2026-93238
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1489
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.0
  2. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <09548edc6114f1eb1035b30795e893204ef45b85
  3. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <4ba8a08f5f26ed59f356a6318bca3aa7cc0af3e2
  4. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <6d554f2571e6b4db242593ba561efd6a6d1f99a9
  5. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <bf09b9d7cd7890bc3a3b7eb63d5ece15f88bfde7
  6. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <f73db632524320d2b93bc8534be8ea875053502d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.0; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <09548edc6114f1eb1035b30795e893204ef45b85; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <4ba8a08f5f26ed59f356a6318bca3aa7cc0af3e2; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <6d554f2571e6b4db242593ba561efd6a6d1f99a9; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <bf09b9d7cd7890bc3a3b7eb63d5ece15f88bfde7; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <f73db632524320d2b93bc8534be8ea875053502d

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1489Service Stop

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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