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NVD / CVE Program· CNA Linux

CVE-2026-45894: iommu/vt-d: Clear Present bit before tearing down PASID entry

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 75ed00055c059dedc47b5daaaa2f8a7a019138ff, 821807c167b7b48a41b95b6607c6b9f97600f7d9, 949d71666e9dd19f21e7b4b53a88cd2c5b902858; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 75ed00055c059dedc47b5daaaa2f8a7a019138ff, 821807c167b7b48a41b95b6607c6b9f97600f7d9, 949d71666e9dd19f21e7b4b53a88cd2c5b902858; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.0 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.14
  • linux linux kernel6.19 and later · before 6.19.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.0affected
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before bed36f5657d34ae982d48045a75bff6113790cf9affected · git
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before c36b0515c6445bd137ec8ad86ef5470c45d6e4bfaffected · git
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before a84d30e8d2bacd21782a6481158b7c9c552f4868affected · git
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before 821807c167b7b48a41b95b6607c6b9f97600f7d9affected · git
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before 949d71666e9dd19f21e7b4b53a88cd2c5b902858affected · git
    • 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 and later · before 75ed00055c059dedc47b5daaaa2f8a7a019138ffaffected · git
    • before 5.0not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-modules-extrabefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-debug-uki-virtbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-develbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-devel-matchedbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-docbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-headersbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-modulesbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-modules-corebefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-modules-extrabefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-modules-extra-matchedbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-rtbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-rt-64kbefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2
AlmaLinux:10kernel-rt-64k-corebefore 6.12.0-211.58.1.el10_26.12.0-211.58.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-45878May 27, 2026 · drm/amdkfd: Fix watch_id bounds checking in debug address watch v2
    31Monitor
  • ← EarlierCVE-2026-45893May 27, 2026 · apparmor: Fix & Optimize table creation from possibly unaligned memory
    28Monitor
  • Later →CVE-2026-45898May 27, 2026 · RDMA/iwcm: Fix workqueue list corruption by removing work_list
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux75ed00055c059dedc47b5daaaa2f8a7a019138ffVendor (CNA)
Linux Linux821807c167b7b48a41b95b6607c6b9f97600f7d9Vendor (CNA)
Linux Linux949d71666e9dd19f21e7b4b53a88cd2c5b902858Vendor (CNA)
Linux Linuxa84d30e8d2bacd21782a6481158b7c9c552f4868Vendor (CNA)
Linux Linuxbed36f5657d34ae982d48045a75bff6113790cf9Vendor (CNA)
Linux Linuxc36b0515c6445bd137ec8ad86ef5470c45d6e4bfVendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.166.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.12.85-1 · Debian:13Package registry (OSV)
red hat:bpftool0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-debuginfo0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-devel0:4.18.0-553.166.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)

+5

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records