CVE-2026-45945

Full vulnerability record from the local CVENow database.

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.

Severity

HIGH

CVSS score

8.8 (v3.1)

Vulnerability status

Modified

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-05-27 14:17:10.790000

Last modified

2026-10-19 20:18:22.137000

View original CVE JSON

{
  "id": "CVE-2026-45945",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-27T14:17:10.790",
  "lastModified": "2026-10-19T20:18:22.137",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Fix race condition during PASID entry replacement\n\nThe Intel VT-d PASID table entry is 512 bits (64 bytes). When replacing\nan active PASID entry (e.g., during domain replacement), the current\nimplementation calculates a new entry on the stack and copies it to the\ntable using a single structure assignment.\n\n        struct pasid_entry *pte, new_pte;\n\n        pte = intel_pasid_get_entry(dev, pasid);\n        pasid_pte_config_first_level(iommu, &new_pte, ...);\n        *pte = new_pte;\n\nBecause the hardware may fetch the 512-bit PASID entry in multiple\n128-bit chunks, updating the entire entry while it is active (Present\nbit set) risks a \"torn\" read. In this scenario, the IOMMU hardware\ncould observe an inconsistent state — partially new data and partially\nold data — leading to unpredictable behavior or spurious faults.\n\nFix this by removing the unsafe \"replace\" helpers and following the\n\"clear-then-update\" flow, which ensures the Present bit is cleared and\nthe required invalidation handshake is completed before the new\nconfiguration is applied."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/iommu/intel/iommu.c",
            "drivers/iommu/intel/nested.c",
            "drivers/iommu/intel/pasid.c",
            "drivers/iommu/intel/pasid.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
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              "versionType": "git",
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              "versionType": "git",
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          "programFiles": [
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            "drivers/iommu/intel/nested.c",
            "drivers/iommu/intel/pasid.c",
            "drivers/iommu/intel/pasid.h"
          ],
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              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
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        "type": "Secondary",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 6.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
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          "role": "CISA Coordinator",
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
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          "value": "CWE-362"
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    {
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      "type": "Secondary",
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  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
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  "references": [
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      "url": "https://git.kernel.org/stable/c/4718007870547e1efebbdd6745d9fce58f008fef",
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}