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CVE-2026-93074 (GCVE-0-2026-93074)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:10 – Updated: 2026-09-18 17:55
VLAI
Title
dax/fsdev: use __va(phys) for kaddr in direct_access
Summary
In the Linux kernel, the following vulnerability has been resolved: dax/fsdev: use __va(phys) for kaddr in direct_access Use __va(phys) instead of virt_addr + linear_offset for the kaddr return in __fsdev_dax_direct_access(). The previous code added a device-linear byte offset to virt_addr (which is __va of ranges[0]), but for multi-range devices with physical gaps between ranges, this linear arithmetic crosses the gap and produces a wrong kernel virtual address. Using __va(phys) where phys comes from dax_pgoff_to_phys() is correct for any range layout because the direct map translates each physical address independently. This leaves dev_dax->virt_addr write-only, so remove the field (suggested by Dave Jiang).
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 759455848df0b9ac3acabdbedcdc4a55af67935f , < 7b642bd3d39105eef4d5908970726c5fda291b53 (git)
Affected: 759455848df0b9ac3acabdbedcdc4a55af67935f , < ff7c73fca793bd5c29a15ba735b0886f62f3a840 (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dax/dax-private.h",
            "drivers/dax/fsdev.c"
          ],
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          "vendor": "Linux",
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          "vendor": "Linux",
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            }
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          "nodes": [
            {
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "7.1",
                  "vulnerable": true
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndax/fsdev: use __va(phys) for kaddr in direct_access\n\nUse __va(phys) instead of virt_addr + linear_offset for the kaddr\nreturn in __fsdev_dax_direct_access(). The previous code added a\ndevice-linear byte offset to virt_addr (which is __va of ranges[0]),\nbut for multi-range devices with physical gaps between ranges, this\nlinear arithmetic crosses the gap and produces a wrong kernel virtual\naddress. Using __va(phys) where phys comes from dax_pgoff_to_phys()\nis correct for any range layout because the direct map translates\neach physical address independently.\n\nThis leaves dev_dax-\u003evirt_addr write-only, so remove the field\n(suggested by Dave Jiang)."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The wrong kaddr is computed in __fsdev_dax_direct_access() from a device pgoff supplied by dax_iomap_pgoff() during local VFS DAX I/O (dax_iomap_rw, dax_zero_iter, dax_fault_iter). No network protocol carries that pgoff.\nAC:L - Once a gapped multi-range fsdev_dax device is bound, any I/O whose pgoff dax_pgoff_to_phys() places in a later range makes virt_addr+offset a deterministic wrong linear-map address; the attacker chooses the file offset that yields that pgoff, with no race.\nPR:L - dax_match_type() never auto-binds DAXDRV_FSDEV_TYPE (admin new_id) and fs_dax_get() is the mount-time holder, but dax_direct_access() then has no capability check, so an unprivileged user with file access on the mounted FS-DAX tree reaches the bad kaddr via read/write/fallocate.\nUI:N - The attacker triggers the bad kaddr solely by their own read, write, fallocate, or page-fault on files they can already open; this is not attacker-supplied media that a victim must mount.\nS:U - dax_copy_from_iter(), dax_copy_to_iter(), and fsdev_write_dax() use the wrong host-kernel __va() pointer; impact stays in the host kernel and does not cross a KVM, IOMMU, or other VM-escape boundary.\nC:H - dax_iomap_iter() calls dax_copy_to_iter() from virt_addr+offset, which for a later range is __va of the physical gap (another dax mapping in the same region, or System RAM), so a file read discloses that memory.\nI:H - dax_copy_from_iter() and fsdev_dax_zero_page_range()\u0027s fsdev_write_dax() write attacker bytes or PAGE_SIZE zeros through the same wrong kaddr into the gap, giving a kernel write into adjacent DAX or RAM.\nA:H - memcpy_flushcache() or copy through a kaddr that lands in an unmapped gap oopses the kernel; even a successful wrong-address write can panic by corrupting adjacent structures."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:55:52.238Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7b642bd3d39105eef4d5908970726c5fda291b53"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff7c73fca793bd5c29a15ba735b0886f62f3a840"
        }
      ],
      "title": "dax/fsdev: use __va(phys) for kaddr in direct_access",
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  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93074",
    "datePublished": "2026-09-17T16:10:57.051Z",
    "dateReserved": "2026-09-17T15:57:05.661Z",
    "dateUpdated": "2026-09-18T17:55:52.238Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-18",
      "epss": "0.00162",
      "percentile": "0.05866"
    },
    "nvd": {
      "cve": {
        "affected": [
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                "product": "Linux",
                "programFiles": [
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                  "drivers/dax/fsdev.c"
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                "vendor": "Linux",
                "versions": [
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                    "versionType": "original_commit_for_fix"
                  }
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              }
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          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndax/fsdev: use __va(phys) for kaddr in direct_access\n\nUse __va(phys) instead of virt_addr + linear_offset for the kaddr\nreturn in __fsdev_dax_direct_access(). The previous code added a\ndevice-linear byte offset to virt_addr (which is __va of ranges[0]),\nbut for multi-range devices with physical gaps between ranges, this\nlinear arithmetic crosses the gap and produces a wrong kernel virtual\naddress. Using __va(phys) where phys comes from dax_pgoff_to_phys()\nis correct for any range layout because the direct map translates\neach physical address independently.\n\nThis leaves dev_dax-\u003evirt_addr write-only, so remove the field\n(suggested by Dave Jiang)."
          }
        ],
        "id": "CVE-2026-93074",
        "lastModified": "2026-09-18T18:18:20.197",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-17T17:18:01.337",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ff7c73fca793bd5c29a15ba735b0886f62f3a840"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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