{"id":"CVE-2026-64071","summary":"nvme-pci: fix use-after-free in nvme_free_host_mem()","details":"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-\u003ehmb_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-\u003ehmb_sgt) but nvme_set_host_mem()\nfails with an I/O error:\n\n  nvme_setup_host_mem()\n    nvme_alloc_host_mem_single()   -\u003e sets dev-\u003ehmb_sgt\n    nvme_set_host_mem()            -\u003e fails with -EIO\n    nvme_free_host_mem()           -\u003e frees hmb_sgt, but does NOT NULL it\n    return error\n\n  nvme_probe() error path:\n    nvme_free_host_mem()           -\u003e dev-\u003ehmb_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-\u003esgl-\u003edma_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  \u003cTASK\u003e\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  \u003c/TASK\u003e\n\nFix this by setting dev-\u003ehmb_sgt to NULL after freeing it, so the\nsecond call takes the multi-descriptor path which safely handles the\nalready-cleaned-up state.","modified":"2026-07-21T03:47:53.066728939Z","published":"2026-07-19T15:39:47.162Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64071.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/7c89f474005d8377525d2991930b7432ee193a52"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9525e3a6fbb1d126a22ab2ee86ddea25af581a7c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b35a13036755c5803168a7cb93bc66035c3e65b8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64071.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64071"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.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"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64071.json"}}],"schema_version":"1.7.5"}