{"cve":"CVE-2026-64071","nvd":{"published":"2026-07-19T16:17:47.687","modified":"2026-09-03T14:54:13.197","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme-pci: fix use-after-free in nvme_free_host_mem()\n\nnvme_free_host_mem() frees dev->hmb_sgt via dma_free_noncontiguous()\nbut never clears the pointer afterward.  This leads to a use-after-free\nif nvme_free_host_mem() is called twice in the same error path.\n\nThis can happen during nvme_probe() when nvme_setup_host_mem() succeeds\nin allocating the HMB (setting dev->hmb_sgt) but nvme_set_host_mem()\nfails with an I/O error:\n\n  nvme_setup_host_mem()\n    nvme_alloc_host_mem_single()   -> sets dev->hmb_sgt\n    nvme_set_host_mem()            -> fails with -EIO\n    nvme_free_host_mem()           -> frees hmb_sgt, but does NOT NULL it\n    return error\n\n  nvme_probe() error path:\n    nvme_free_host_mem()           -> dev->hmb_sgt is stale, use-after-free\n\nThe second call dereferences the freed sgt, causing a NULL pointer\ndereference in iommu_dma_free_noncontiguous() when it accesses\nsgt->sgl->dma_address (the backing memory has been freed and zeroed).\n\nThis is reproducible on Thunderbolt-attached NVMe devices (e.g., OWC\nEnvoy Express behind a Dell WD22TB4 dock) where the device intermittently\nreturns I/O errors during HMB setup due to PCIe link instability.\n\n BUG: kernel NULL pointer dereference, address: 0000000000000010\n RIP: 0010:iommu_dma_free_noncontiguous+0x22/0x80\n Call Trace:\n  <TASK>\n  dma_free_noncontiguous+0x3b/0x130\n  nvme_free_host_mem+0x30/0xf0 [nvme]\n  nvme_probe.cold+0xcc/0x275 [nvme]\n  local_pci_probe+0x43/0xa0\n  pci_device_probe+0xeea/0x290\n  really_probe+0xf9/0x3b0\n  __driver_probe_device+0x8b/0x170\n  driver_probe_device+0x24/0xd0\n  __driver_attach_async_helper+0x6b/0x110\n  async_run_entry_fn+0x37/0x170\n  process_one_work+0x1ac/0x3d0\n  worker_thread+0x1b8/0x360\n  kthread+0xf7/0x130\n  ret_from_fork+0x2d8/0x3a0\n  ret_from_fork_asm+0x1a/0x30\n  </TASK>\n\nFix this by setting dev->hmb_sgt to NULL after freeing it, so the\nsecond call takes the multi-descriptor path which safely handles the\nalready-cleaned-up state.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/7c89f474005d8377525d2991930b7432ee193a52","https://git.kernel.org/stable/c/9525e3a6fbb1d126a22ab2ee86ddea25af581a7c","https://git.kernel.org/stable/c/b35a13036755c5803168a7cb93bc66035c3e65b8"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-64071","score":0.00133,"percentile":0.02793,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}