FKIE_CVE-2026-98262

Vulnerability from fkie_nvd - Published: 2026-10-06 09:18 - Updated: 2026-10-06 09:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/ata/libahci.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0191c9ff23ef1678dbfb5ad253a2dee92feb5d71",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "8f510f68208a1f673d7c7234a687be4671490e9c",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "4719424bb7cb9f20b73986bcb72dd528f0e5c6eb",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "a5a8b4737f68bbac8aa0685af0c8921e6003c22b",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "b28a17d4a9bb0aa38b48681c3927b012ba40eabe",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "b691a3e244278362e552439d6d3ee5a5d3703488",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "7912ad8fb5233bb8cfe21d50df639c7f4854ff9d",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            },
            {
              "lessThan": "82e47533221d4746947b74d2e79a478c36c6433a",
              "status": "affected",
              "version": "c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/ata/libahci.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.22"
            },
            {
              "lessThan": "2.6.22",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY\n\nA user reported that commit 105c42566a55 (\"ata: ahci: force 32-bit DMA for\nJMicron JMB582/JMB585\") made the JMicron JMB585 unusable on his board.\n\nThe failure is seen as soon as the ahci driver is probed, and booting with\niommu=off does not solve the problem.\n\nLooking at the AHCI specification, PxCLBU and PxFBU are both read only \u00270\u0027\nfor HBAs that do not support 64-bit addressing.\n\nFor HBAs that do support 64-bit addressing, the registers are read write,\nwith a reset value that is Implementation Specific.\n\nWhen using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit\naddressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64.\nThus, in this case, we need to explicitly clear the registers to 0."
    }
  ],
  "id": "CVE-2026-98262",
  "lastModified": "2026-10-06T09:18:15.347",
  "metrics": {},
  "published": "2026-10-06T09:18:15.347",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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