nvme-pci: fix use-after-free in nvme_free_host_mem()

{
  "id": "44d8ba2d07cd8a011b2f0d69d0d97ae55a645afde6208bf47d629ac8584ab401",
  "url": "https://osv.dev/vulnerability/CVE-2026-64071",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nvme-pci: fix use-after-free in nvme_free_host_mem()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nvme-pci: fix use-after-free in nvme_free_host_mem() nvme_free_host_mem() frees dev->hmb_sgt via dma_free_noncontiguous() but never clears the pointer afterward. This leads to a use-after-free if nvme_free_host_mem() is called twice in the same error path. This can happen during nvme_probe() when nvme_setup_host_mem() succeeds in allocating the HMB (setting dev->hmb_sgt) but nvme_set_host_mem() fails with an I/O error: nvme_setup_host_mem() nvme_alloc_host_mem_single() -> sets dev->hmb_sgt nvme_set_host_mem() -> fails with -EIO nvme_free_host_mem() -> frees hmb_sgt, but does NOT NULL it return error nvme_probe() error path: nvme_free_host_mem() -> dev->hmb_sgt is stale, use-after-free The second call dereferences the freed sgt, causing a NULL pointer dereference in iommu_dma_free_noncontiguous() when it accesses sgt->sgl->dma_address (the backing memory has been freed and zeroed). This is reproducible on Thunderbolt-attached NVMe devices (e.g., OWC Envoy Express behind a Dell WD22TB4 dock) where the device intermittently returns I/O errors during HMB setup due to PCIe link instability. BUG: kernel NULL pointer dereference, address: 0000000000000010 RIP: 0010:iommu_dma_free_noncontiguous+0x22/0x80 Call Trace: dma_free_noncontiguous+0x3b/0x130 nvme_free_host_mem+0x30/0xf0 [nvme] nvme_probe.cold+0xcc/0x275 [nvme] local_pci_probe+0x43/0xa0 pci_device_probe+0xeea/0x290 really_probe+0xf9/0x3b0 __driver_probe_device",
    "evidence": "osv:CVE-2026-64071",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.34",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-64071",
      "aliases": [
        "CVE-2026-64071"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "63a5c7a4b4c49ad86c362e9f555e6f343804ee1d"
                },
                {
                  "fixed": "9525e3a6fbb1d126a22ab2ee86ddea25af581a7c"
                },
                {
                  "fixed": "7c89f474005d8377525d2991930b7432ee193a52"
                },
                {
                  "fixed": "b35a13036755c5803168a7cb93bc66035c3e65b8"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64071.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.34"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64071.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.257699284Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/7c89f474005d8377525d2991930b7432ee193a52",
        "https://git.kernel.org/stable/c/9525e3a6fbb1d126a22ab2ee86ddea25af581a7c",
        "https://git.kernel.org/stable/c/b35a13036755c5803168a7cb93bc66035c3e65b8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64071.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64071",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64071.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64071",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 501254,
  "published_at": "2026-07-19T15:39:47.162+00:00"
}