CVE-2026-64071: nvme-pci: fix use-after-free in nvme_free_host_mem()

High 7.8 EPSS 0.1% Linux kernel

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: <TASK> 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+0x8b/0x170 driver_probe_device+0x24/0xd0 __driver_attach_async_helper+0x6b/0x110 async_run_entry_fn+0x37/0x170 process_one_work+0x1ac/0x3d0 worker_thread+0x1b8/0x360 kthread+0xf7/0x130 ret_from_fork+0x2d8/0x3a0 ret_from_fork_asm+0x1a/0x30 </TASK> Fix this by setting dev->hmb_sgt to NULL after freeing it, so the second call takes the multi-descriptor path which safely handles the already-cleaned-up state.

• CVE-2026-64071CVE identifier
• 7.8CVSS 3.1 base score (high)
• 0.1%EPSS: chance of exploitation in the next 30 days (higher than 3% of CVEs)
• 2026-07-19published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

Affected and fixed versions

Affected:

• Linux Linux 63a5c7a4b4c49ad86c362e9f555e6f343804ee1d to before 9525e3a6fbb1d126a22ab2ee86ddea25af581a7c
• Linux Linux 63a5c7a4b4c49ad86c362e9f555e6f343804ee1d to before 7c89f474005d8377525d2991930b7432ee193a52
• Linux Linux 63a5c7a4b4c49ad86c362e9f555e6f343804ee1d to before b35a13036755c5803168a7cb93bc66035c3e65b8
• Linux Linux 6.13

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

sudo apt update
sudo apt install --only-upgrade linux-image-amd64

sudo apt update
sudo apt install --only-upgrade linux-image-generic (or the installed flavour: linux-image-aws, -azure, -gcp, -virtual)

sudo dnf upgrade --refresh kernel

sudo dnf upgrade --refresh kernel

sudo zypper refresh
sudo zypper update kernel-default

sudo dnf upgrade --releasever=latest kernel kernel6.12

sudo pacman -Syu

apk update && apk upgrade linux-lts linux-virt

not Linux

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

Fix status in Linux distributions

From the Debian security tracker, Ubuntu CVE tracker and Red Hat Security Data API, refreshed every few hours.

Sources

• https://git.kernel.org/stable/c/9525e3a6fbb1d126a22ab2ee86ddea25af581a7c
• https://git.kernel.org/stable/c/7c89f474005d8377525d2991930b7432ee193a52
• https://git.kernel.org/stable/c/b35a13036755c5803168a7cb93bc66035c3e65b8
• CVE-2026-64071 on CVE.org
• CVE-2026-64071 on NVD

Page generated automatically from official sources on 2026-11-03 18:05 UTC. Always confirm with your vendor's advisory.