Linux KernelOperating system · Linux
CVE-2026-45894
A fix is available.
Upgrade to 6.12.75 / 6.18.14 or later.
See remediation →
80/100
Remediation priority · High
Zero-click
Patch available
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA detailed technical summary for this CVE is being prepared.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
Affected:
>= 5.0, < 6.12.75>= 6.13, < 6.18.14>= 6.19, < 6.19.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped
Upgrade available
Upgrade to 6.12.75 / 6.18.14 / 6.19.4 or later
Fixed in
6.12.756.18.146.19.4
Vendor patch
git.kernel.org →
Recommended fix
High confidence
6.12.75 (for 5.0-6.12 kernels), 6.18.14 (for 6.13-6.17 kernels), or 6.19.4 (for 6.18-6.19 kernels)
- Identify the currently running kernel version using `uname -r`
- Determine which major kernel series you are on (5.x, 6.12.x, 6.13.x-6.17.x, or 6.18.x-6.19.x)
- For kernels 5.0 to 6.12.x: upgrade to kernel version 6.12.75 or later
- For kernels 6.13.x to 6.17.x: upgrade to kernel version 6.18.14 or later
- For kernels 6.18.x to 6.19.x: upgrade to kernel version 6.19.4 or later
- After upgrade, reboot the system to load the patched kernel
- Verify the fix is applied by checking the IOMMU driver code in `/drivers/iommu/intel/pasid.h` or `/drivers/iommu/intel/pasid.c` for the presence of dma_wmb() calls around Present bit operations
Caveat Kernel upgrades may require matching user-space tools; ensure bootloader configuration is updated to boot the new kernel
Generated from the published advisory — verify against the referenced sources before acting.
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-45894 in production — separate from our analysis above.
Know something about CVE-2026-45894?
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- A config change or rule that shut the vector down
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