CVE-2026-98815

Low risk· EPSS 9%

Published: 18/10/2026(UTC)Updated: 26/10/2026(UTC)Translated: 18/10/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.20%

9th percentile - higher than 9% of all known CVEs

Summary

A use-after-free vulnerability exists in the Linux kernel NVMe driver related to the character device (cdev) lifetime. In multipath mode, when the NS head is torn down, already-open file descriptors remain active, allowing access to freed memory after the nvme_ns_head reference count drops to zero.

Risk Assessment

A local attacker or privileged process could trigger a kernel panic or potentially exploit the use-after-free for privilege escalation. The risk affects systems using NVMe in multipath mode, especially during dynamic controller removal.

Recommendation

Update the Linux kernel to a version containing the fix for CVE-2026-98815. Until patched, avoid simultaneously opening /dev/ng* devices and tearing down NVMe controllers in multipath mode.

Other vulnerabilities in Linux kernel NVMe driver

CVE-2026-89483High
A vulnerability was fixed in the Linux kernel NVMe driver where nvme_setup_discard() fell back to the per-controller ctrl->discard_page on allocation failure, which was never zeroed. As a result, up to 4080 bytes of uninitialized memory from the page's previous contents were sent to the NVMe controller.

Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: nvme: fix cdev lifetime Sashiko bot reported a potential problem for the cdev lifetime in [0] - the code there is heavily based on the NVMe code. Currently the NS head .open and .release file_operations methods take and put a reference to the nvme_ns_head to ensure that this structure does not disappear while we open fds for that cdev. In multipath mode, when we teardown the NS head, we call nvme_cdev_del() -> cdev_device_del() -> cdev_del(). However after cdev_del() returns, cdevs already open will remain and their fops will still be callable. As such, we can still reference the cdev after the nvme_ns_head reference count drops to 0 (and is freed). This can be shown with an application which delays between opening the cdev and issuing the ioctl while the NS head is being torn down: # ./ioctl_file /dev/ng1n1 & # waiting 10 seconds .... # ./ini_nvme_teardown.sh [ 21.221718] nvme nvme1: Removing ctrl: NQN "nvme-test-target" [ 21.274609] nvme nvme2: Removing ctrl: NQN "nvme-test-target" # now going to issue ioctl .... [ 26.549285] ================================================================== [ 26.550841] BUG: KASAN: slab-use-after-free in cdev_put.part.0+0x3d/0x40 [ 26.552352] Read of size 8 at addr ffff88811e7fa170 by task ioctl_file/237 [ 26.553805] [ 26.554227] CPU: 3 UID: 0 PID: 237 Comm: ioctl_file Not tainted 7.2.0-rc1-00004-g6852a10e32d4 #921 PREEMPT(lazy) [ 26.554236] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 26.554241] Call Trace: [ 26.554245] <TASK> [ 26.554248] dump_stack_lvl+0x68/0xa0 [ 26.554266] print_report+0x10d/0x5d0 [ 26.554276] ? __virt_addr_valid+0x21d/0x3f0 [ 26.554287] ? cdev_put.part.0+0x3d/0x40 [ 26.554292] kasan_report+0x96/0xd0 [ 26.554300] ? cdev_put.part.0+0x3d/0x40 [ 26.554307] cdev_put.part.0+0x3d/0x40 [ 26.554313] __fput+0x7bc/0xa70 [ 26.554322] fput_close_sync+0xd8/0x190 [ 26.554328] ? __pfx_fput_close_sync+0x10/0x10 [ 26.554337] __x64_sys_close+0x79/0xd0 [ 26.554344] do_syscall_64+0x117/0x6b0 [ 26.554351] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 26.554358] RIP: 0033:0x7f938c067727 [ 26.554364] Code: 48 89 fa 4c 89 df e8 28 ad 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5bf [ 26.554369] RSP: 002b:00007fff49f05980 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 [ 26.554376] RAX: ffffffffffffffda RBX: 00007f938bfd7780 RCX: 00007f938c067727 [ 26.554380] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 [ 26.554383] RBP: 00007fff49f05a10 R08: 0000000000000000 R09: 0000000000000000 [ 26.554386] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 [ 26.554389] R13: 00007fff49f05b40 R14: 00007f938c207000 R15: 000055c148471d78 [ 26.554397] </TASK> [ 26.554399] [ 26.575612] Allocated by task 100: [ 26.575871] kasan_save_stack+0x24/0x50 [ 26.576157] kasan_save_track+0x14/0x30 [ 26.576418] __kasan_kmalloc+0x7f/0x90 [ 26.576668] __kmalloc_noprof+0x281/0x6c0 [ 26.576938] nvme_alloc_ns+0x7f7/0x3170 [ 26.577206] nvme_scan_ns+0x508/0x880 [ 26.577449] async_run_entry_fn+0x8c/0x350 [ 26.577723] process_scheduled_works+0xb6f/0x1a00 [ 26.578034] worker_thread+0x4ad/0xb40 [ 26.578283] kthread+0x34f/0x450 [ 26.578501] ret_from_fork+0x563/0x800 [ 26.578752] ret_from_fork_asm+0x1a/0x30 [ 26.579012] [ 26.579124] Freed by task 237: [ 26.579335] kasan_save_stack+0x24/0x50 [ 26.579596] kasan_save_track+0x14/0x30 [ 26.579855] kasan_save_free_info+0x3a/0x60 [ 26.580131] __kasan_slab_free+0x43/0x70 [ 26.580388] kfree+0x321/0x500 [ 26.580591] nvme_ns_head_chr_release+0x39/0x50 [ 26.580883] __fput+0x352/0xa70 [ 26.581095] fput_close_sync+0xd8/0x190 [ 26.581350] __x64_sys_close+0x79/0xd0 [ 26.581595] do_syscall_64+0x117/0x6b0 [ 26.581842] entry_SYSCAL ---truncated---

Vulnerability data from NVD (NIST) · CISA KEV · EPSS