---
id: CVE-2026-89448
title: >-
  kernel: iommu/vt-d: Force requesting ACS when tboot is enabled
  (CVE-2026-89448)
summary: >-
  A flaw was found in the Linux kernel's IOMMU (Input/Output Memory Management
  Unit) component. When tboot (Trusted Boot) is enabled, the system may fail to
  correctly request Access Control Services (ACS). This misconfiguration could
  potenti…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-358
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T19:54:55+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89448.json'
references:
  - 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
  - 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'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00144
epssPercentile: 0.0402
scores:
  vendor: 7
  cna: 9.3
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

A flaw was found in the Linux kernel's IOMMU (Input/Output Memory Management Unit) component. When tboot (Trusted Boot) is enabled, the system may fail to correctly request Access Control Services (ACS). This misconfiguration could potentially lead to a bypass of intended Access Control Services, which are designed to enforce security policies for I/O devices.

## 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)

**kernel: iommu/vt-d: Force requesting ACS when tboot is enabled** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

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

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7

## Remediation

Affected