# CVE-2026-80787: nvmet: pci-epf: fix use-after-free in nvmet_pci_epf_exec_iod_work()

> A use-after-free vulnerability in the Linux kernel's NVMe PCI endpoint function driver allows local attackers to cause a denial of service or potentially execute code.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-80787, DEBIAN-CVE-2026-80787, GHSA-xprc-p39c-6w43, UBUNTU-CVE-2026-80787

## What is CVE-2026-80787?

CVE-2026-80787 is an use after free vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

nvmet: pci-epf: fix use-after-free in nvmet_pci_epf_exec_iod_work()

nvmet_pci_epf_exec_iod_work() submits an I/O command with req->execute()
and then waits for the command to complete and transfers the data back
to the host. This wait is not needed for commands that do not transfer
data from the device to the host. To decide whether that wait is needed,
it reads iod->data_len and iod->dma_dir after calling req->execute().

However, once req->execute() is called, the command may complete
asynchronously on another CPU. For commands that do not require a
device-to-host data transfer, nvmet_pci_epf_queue_response() calls
nvmet_pci_epf_complete_iod() directly, which can free the iod before it
reads iod->data_len and iod->dma_dir, resulting in the KFENCE use-after-
free:

 BUG: KFENCE: use-after-free read in nvmet_pci_epf_exec_iod_work+0x288/0x798 [nvmet_pci_epf]

 Use-after-free read at 0x00000000fdfa6d03 (in kfence-#63):
  nvmet_pci_epf_exec_iod_work+0x288/0x798 [nvmet_pci_epf]
  process_one_work+0x15c/0x4f0
  worker_thread+0x18c/0x30c
  kthread+0x130/0x140
  ret_from_fork+0x10/0x20

 kfence-#63: 0x00000000e3de0e71-0x00000000c938ad62, size=712, cache=kmalloc-1k

 allocated by task 10 on cpu 0 at 73.995480s (0.005122s ago):
  mempool_kmalloc+0x1c/0x28
  mempool_alloc_noprof+0x40/0x9c
  nvmet_pci_epf_poll_sqs_work+0xd4/0x344 [nvmet_pci_epf]
  process_one_work+0x15c/0x4f0
  worker_thread+0x18c/0x30c
  kthread+0x130/0x140
  ret_from_fork+0x10/0x20

 freed by task 131 on cpu 3 at 73.995521s (0.008385s ago):
  mempool_kfree+0x10/0x20
  mempool_free+0x44/0x64
  nvmet_pci_epf_free_iod+0x88/0x98 [nvmet_pci_epf]
  nvmet_pci_epf_cq_work+0xfc/0x280 [nvmet_pci_epf]
  process_one_work+0x15c/0x4f0
  worker_thread+0x18c/0x30c
  kthread+0x130/0x140
  ret_from_fork+0x10/0x20

Fix this by referring to iod->data_len and iod->dma_dir before calling
req->execute(). The remaining iod accesses such as iod->status are only
reached on the device-to-host read path. In this case,
nvmet_pci_epf_queue_response() signals iod->done instead of freeing the
iod, so the iod stays valid.

## Which versions are affected by CVE-2026-80787?


## How do I fix CVE-2026-80787?

Apply the vendor's patch.

## Is CVE-2026-80787 being exploited?

There is no known exploitation of CVE-2026-80787 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80787 and fix it if it is affected.

What it is: CVE-2026-80787 is an use after free vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80787 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80787/ (Markdown: https://insights.sbomify.com/CVE-2026-80787/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80787
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80787
- OSV: https://osv.dev/vulnerability/CVE-2026-80787

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80787/
Summaries are generated and may contain mistakes; the official description above is the record.