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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-80787 being exploited?
There is no known exploitation of CVE-2026-80787 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80787, DEBIAN-CVE-2026-80787, GHSA-xprc-p39c-6w43, UBUNTU-CVE-2026-80787.