{"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":0.0401,"scores":{"vendor":7,"cna":9.3},"ingestedAt":"2026-09-14T15:23:07.453Z","slug":"CVE-2026-89448","body":"## Overview\n\nA 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.\n\n## Vendor advisories\n\n- **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)\n\n**kernel: iommu/vt-d: Force requesting ACS when tboot is enabled** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNot affected:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n\n## Remediation\n\nAffected","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":207002,"id":"CVE-2026-89448","ts":1789749736439,"field":"cvss","old":"9.3","new":"7"},{"seq":207001,"id":"CVE-2026-89448","ts":1789749736439,"field":"severity","old":"critical","new":"high"},{"seq":198053,"id":"CVE-2026-89448","ts":1789384321566,"field":"cvss","old":"4.1","new":"9.3"},{"seq":198052,"id":"CVE-2026-89448","ts":1789384321566,"field":"severity","old":"medium","new":"critical"},{"seq":183544,"id":"CVE-2026-89448","ts":1789356675821,"field":"cvss","old":"9.3","new":"4.1"},{"seq":183543,"id":"CVE-2026-89448","ts":1789356675821,"field":"severity","old":"critical","new":"medium"},{"seq":153230,"id":"CVE-2026-89448","ts":1789285349645,"field":"cvss","old":null,"new":"9.3"},{"seq":153229,"id":"CVE-2026-89448","ts":1789285349645,"field":"severity","old":"none","new":"critical"}]}