Medium [CVE-2026-89448] Linux kernel: IOMMU misconfiguration when tboot is enabled
This medium-severity Red Hat Linux advisory covers CVE-2026-89448 affecting Red Hat OpenShift Container Platform 4.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
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 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(). 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.
Red Hat severity: Moderate — CVSS 4.1 (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-358.
Affected Red Hat products: Red Hat OpenShift Container Platform 4. Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.