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VulnerabilityPublished Updated

CVE-2026-45945: Linux kernel · iommu/vt-d: Fix race condition during PASID entry replacement

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in c3b1edea3791fa91ab7032faa90355913ad9451b : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in c3b1edea3791fa91ab7032faa90355913ad9451b, 4718007870547e1efebbdd6745d9fce58f008fef, 66a7aff480a82b8642b3991fed5fdc9780022157
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Linux kernel to c3b1edea3791fa91ab7032faa90355913ad9451b, 4718007870547e1efebbdd6745d9fce58f008fef or 66a7aff480a82b8642b3991fed5fdc9780022157.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7543ee63e8113aa34b07df3b16b3b9d2c5f73939, < c3b1edea3791fa91ab7032faa90355913ad9451b
Fixed in
  • c3b1edea3791fa91ab7032faa90355913ad9451b
LinuxLinuxAffected
  • ≥ 7543ee63e8113aa34b07df3b16b3b9d2c5f73939, < 4718007870547e1efebbdd6745d9fce58f008fef
Fixed in
  • 4718007870547e1efebbdd6745d9fce58f008fef
LinuxLinuxAffected
  • ≥ 7543ee63e8113aa34b07df3b16b3b9d2c5f73939, < 66a7aff480a82b8642b3991fed5fdc9780022157
Fixed in
  • 66a7aff480a82b8642b3991fed5fdc9780022157
LinuxLinuxAffected
  • =6.13
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix race condition during PASID entry replacement The Intel VT-d PASID table entry is 512 bits (64 bytes). When replacing an active PASID entry (e.g., during domain replacement), the current implementation calculates a new entry on the stack and copies it to the table using a single structure assignment. struct pasid_entry *pte, new_pte; pte = intel_pasid_get_entry(dev, pasid); pasid_pte_config_first_level(iommu, &new_pte, ...); *pte = new_pte; Because the hardware may fetch the 512-bit PASID entry in multiple 128-bit chunks, updating the entire entry while it is active (Present bit set) risks a "torn" read. In this scenario, the IOMMU hardware could observe an inconsistent state — partially new data and partially old data — leading to unpredictable behavior or spurious faults. Fix this by removing the unsafe "replace" helpers and following the "clear-then-update" flow, which ensures the Present bit is cleared and the required invalidation handshake is completed before the new configuration is applied.

References

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