---
id: CVE-2026-89448
title: 'iommu/vt-d: Force requesting ACS when tboot is enabled'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  iommu/vt-d: Force requesting ACS when tboot is enabled

  Currently the conditions of requesting ACS in detect_intel_iommu()
  don't include tboot, leading to a possible mi…
severity: critical
cvss: 9.3
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-358
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a <
    579eb867d3da63f3b5e32f235925e1daa7ec70d0
  - >-
    Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a <
    aaeb81241e802c86be69394f72d49fde3f861fbb
  - >-
    Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a <
    45705a6bfdb283f7b3b509010fd617b72f942537
  - >-
    Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a <
    87bc611c6c98a41c00feb7b06b0c297dd141a2ae
  - >-
    Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a <
    607432b2618b61df81134be0ef2562b8300c1216
  - Linux 2.6.33
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:22:16.872682Z'
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:46:57.768Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89448'
references:
  - url: 'https://git.kernel.org/stable/c/579eb867d3da63f3b5e32f235925e1daa7ec70d0'
  - url: 'https://git.kernel.org/stable/c/aaeb81241e802c86be69394f72d49fde3f861fbb'
  - url: 'https://git.kernel.org/stable/c/45705a6bfdb283f7b3b509010fd617b72f942537'
  - url: 'https://git.kernel.org/stable/c/87bc611c6c98a41c00feb7b06b0c297dd141a2ae'
  - url: 'https://git.kernel.org/stable/c/607432b2618b61df81134be0ef2562b8300c1216'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89448.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89448'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532174'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89448'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89448'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89448.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00142
epssPercentile: 0.03453
scores:
  cna: 9.3
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

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

iommu/vt-d: Force requesting ACS when tboot is enabled

Currently the conditions of requesting ACS in detect_intel_iommu()
don't include tboot, leading to a possible misconfiguration with ACS
disabled (e.g. due to user opts) while iommu is later forced on by
tboot_force_iommu().

Fix it by checking tboot in detect_intel_iommu().

## Affected

- `Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a < 579eb867d3da63f3b5e32f235925e1daa7ec70d0`
- `Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a < aaeb81241e802c86be69394f72d49fde3f861fbb`
- `Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a < 45705a6bfdb283f7b3b509010fd617b72f942537`
- `Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a < 87bc611c6c98a41c00feb7b06b0c297dd141a2ae`
- `Linux >= 5d990b627537e59a3a2f039ff588a4750e9c1a6a < 607432b2618b61df81134be0ef2562b8300c1216`
- `Linux 2.6.33`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89448.json)