CVE-2026-89957

Guest hardware access retained after hot-unplug

Published Sep 16, 2026 · Updated Sep 16, 2026

Improper access control in Linux allows guest OS users to retain access to unplugged AP devices after host configuration changes. vfio_ap_mdev_hot_unplug_cfg treats an empty bitmap_andnot result as no change, so it skips the guest APCB update after clearing the final assigned resource. Reachability requires an s390 host using VFIO AP mediated devices and removal of the guest's last assigned adapter, domain, or control domain; the guest then keeps stale hardware access.

CVSS severityUnavailable
Unscored
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Linux allows guest OS users to retain access to unplugged AP devices after host configuration changes. vfio_ap_mdev_hot_unplug_cfg treats an empty bitmap_andnot result as no change, so it skips the guest APCB update after clearing the final assigned resource. Reachability requires an s390 host using VFIO AP mediated devices and removal of the guest's last assigned adapter, domain, or control domain; the guest then keeps stale hardware access.

The record

CVE
CVE-2026-89957
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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 <04b35dd88c108b2d2ceaaa396aba1cb4049d5831
  3. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <3a9b049bbdc40165d7f3e20b818eec95e5694d96
  4. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <753aa3bb1273bc0d36adb013d5915cc8ff6b72a9
  5. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <917f509bfb88048094dbb85c4e9dbc4d6fe4a886
  6. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <c45753c32d452d10d8efaeb52587e9e6e8126e33
  7. Affected versionversion=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <f58e824de8577fe411f6199d659731a0f86a7275

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.0; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <04b35dd88c108b2d2ceaaa396aba1cb4049d5831; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <3a9b049bbdc40165d7f3e20b818eec95e5694d96; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <753aa3bb1273bc0d36adb013d5915cc8ff6b72a9; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <917f509bfb88048094dbb85c4e9dbc4d6fe4a886; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <c45753c32d452d10d8efaeb52587e9e6e8126e33; version=eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 <f58e824de8577fe411f6199d659731a0f86a7275

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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