CVE-2026-98262 (GCVE-0-2026-98262)
Vulnerability from cvelistv5
Published
2026-10-06 08:45
Modified
2026-10-19 09:16
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
Impacted products
Vendor Product Version
Linux Linux Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
Version: c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/ata/libahci.c"
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          "vendor": "Linux",
          "versions": [
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            },
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            {
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            },
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              "versionType": "original_commit_for_fix"
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          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:16:33.319Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c"
        },
        {
          "url": "https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b"
        },
        {
          "url": "https://git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe"
        },
        {
          "url": "https://git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488"
        },
        {
          "url": "https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d"
        },
        {
          "url": "https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a"
        }
      ],
      "title": "ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98262",
    "datePublished": "2026-10-06T08:45:26.118Z",
    "dateReserved": "2026-09-25T10:25:14.332Z",
    "dateUpdated": "2026-10-19T09:16:33.319Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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