Skip to content
Fencer Vulns
high 7.8

CVE-2026-45894 json

iommu/vt-d: Clear Present bit before tearing down PASID entry

published 2026-05-27 5 mo ago modified 2026-10-30 10 d ago also EUVD-2026-32360

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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

iommu/vt-d: Clear Present bit before tearing down PASID entry

The Intel VT-d Scalable Mode PASID table entry consists of 512 bits (64 bytes). When tearing down an entry, the current implementation zeros the entire 64-byte structure immediately using multiple 64-bit writes.

Since the IOMMU hardware may fetch these 64 bytes using multiple internal transactions (e.g., four 128-bit bursts), updating or zeroing the entire entry while it is active (P=1) risks a "torn" read. If a hardware fetch occurs simultaneously with the CPU zeroing the entry, the hardware could observe an inconsistent state, leading to unpredictable behavior or spurious faults.

Follow the "Guidance to Software for Invalidations" in the VT-d spec (Section 6.5.3.3) by implementing the recommended ownership handshake:

1. Clear only the 'Present' (P) bit of the PASID entry. 2. Use a dma_wmb() to ensure the cleared bit is visible to hardware before proceeding. 3. Execute the required invalidation sequence (PASID cache, IOTLB, and Device-TLB flush) to ensure the hardware has released all cached references. 4. Only after the flushes are complete, zero out the remaining fields of the PASID entry.

Also, add a dma_wmb() in pasid_set_present() to ensure that all other fields of the PASID entry are visible to the hardware before the Present bit is set.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.75, 6.18.14, 6.19.4, 7.0
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.18.14-1

debian advisories DEBIAN-CVE-2026-45894

  • linux-nvidia-tegra Ubuntu 24.04 LTS 6.8.0-1035.38

ubuntu advisories UBUNTU-CVE-2026-45894

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.58.1.el10_2
  • rv RHEL 10.2 6.12.0-211.58.1.el10_2
  • perf RHEL 10.2 6.12.0-211.58.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.58.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.58.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.58.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.58.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.58.1.el10_2

red hat advisories RHSA-2026:70498RHSA-2026:70459RHSA-2026:70403RHSA-2026:70402

  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.36.1
  • kernel-obs-build Linux Micro Extras 6.2 6.12.0-160000.36.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.36.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.36.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.36.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.36.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.36.1.160000.2.17
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.36.1

suse advisories SUSE-SU-2026:22742-1SUSE-SU-2026:22769-1SUSE-SU-2026:22835-1SUSE-SU-2026:22812-1SUSE-SU-2026:2799-1SUSE-SU-2026:2722-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.36.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.36.1

opensuse advisories openSUSE-SU-2026:21388-1

  • rv AlmaLinux 10 6.12.0-211.58.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.58.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.58.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.58.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.58.1.el10_2
  • kernel-tools AlmaLinux 10 6.12.0-211.58.1.el10_2
  • python3-perf AlmaLinux 10 6.12.0-211.58.1.el10_2
  • kernel-rt-64k AlmaLinux 10 6.12.0-211.58.1.el10_2

almalinux advisories ALSA-2026:70498ALSA-2026:70402ALSA-2026:70403ALSA-2026:70459

  • kernel Rocky Linux 9 5.14.0-687.50.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.58.1.el10_2
  • kernel-rt Rocky Linux 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel Rocky Linux 8 4.18.0-553.166.1.el8_10

rocky linux advisories RLSA-2026:70459RLSA-2026:70498RLSA-2026:70403RLSA-2026:70402

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-45894 updated cvss 4.7

kernel: iommu/vt-d: Clear Present bit before tearing down PASID entry

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.50.1.el9_8, perf 5.14.0-687.50.1.el9_8, rtla 5.14.0-687.50.1.el9_8, python3-perf 5.14.0-687.50.1.el9_8, kernel-devel-matched 5.14.0-687.50.1.el9_8, kernel-64k-devel-matched 5.14.0-687.50.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.58.1.el10_2, perf 6.12.0-211.58.1.el10_2, rtla 6.12.0-211.58.1.el10_2, python3-perf 6.12.0-211.58.1.el10_2, kernel-devel-matched 6.12.0-211.58.1.el10_2, kernel-64k-devel-matched 6.12.0-211.58.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.166.1.el8_10, kernel 4.18.0-553.166.1.el8_10, bpftool 4.18.0-553.166.1.el8_10, kernel-core 4.18.0-553.166.1.el8_10, kernel-tools 4.18.0-553.166.1.el8_10, python3-perf 4.18.0-553.166.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.50.1.el9_8, kernel-64k 5.14.0-687.50.1.el9_8, kernel-core 5.14.0-687.50.1.el9_8, kernel-tools 5.14.0-687.50.1.el9_8, kernel-modules 5.14.0-687.50.1.el9_8, kernel-64k-core 5.14.0-687.50.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.58.1.el10_2, kernel-64k 6.12.0-211.58.1.el10_2, kernel-core 6.12.0-211.58.1.el10_2, kernel-tools 6.12.0-211.58.1.el10_2, kernel-modules 6.12.0-211.58.1.el10_2, kernel-64k-core 6.12.0-211.58.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.50.1.el9_8
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.58.1.el10_2
    fixed: vendor fix RHSA-2026:70498
show 8 more
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.166.1.el8_10
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, +4 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.50.1.el9_8, kernel-rt-64k 5.14.0-687.50.1.el9_8, kernel-rt-core 5.14.0-687.50.1.el9_8, kernel-rt-modules 5.14.0-687.50.1.el9_8, kernel-rt-64k-core 5.14.0-687.50.1.el9_8, kernel-rt-debug-core 5.14.0-687.50.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-64k 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-64k-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.50.1.el9_8, kernel-rt-core 5.14.0-687.50.1.el9_8, kernel-rt-modules 5.14.0-687.50.1.el9_8, kernel-rt-debug-core 5.14.0-687.50.1.el9_8, kernel-rt-modules-core 5.14.0-687.50.1.el9_8, kernel-rt-debug-modules 5.14.0-687.50.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, kernel-rt-modules-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-modules 6.12.0-211.58.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules-extra 4.18.0-553.166.1.rt7.507.el8_10, +2 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.