---
id: CVE-2026-98723
title: 'nvmet: copy the hostid into the ctrl before creating PR pc_refs'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nvmet: copy the hostid into the ctrl before creating PR pc_refs

  Commit 6202783184bf ("nvmet: Improve nvmet_alloc_ctrl() interface and
  implementation") added a second u…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <
    d3d6d7efdacc08616d23b3ac42272a494951dc0f
  - >-
    Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <
    23194531595c5d1d4454e3a607b0c8fc0c4e8695
  - >-
    Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd <
    5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62
  - Linux 6.15
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:46:59.444Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98723'
references:
  - url: 'https://git.kernel.org/stable/c/d3d6d7efdacc08616d23b3ac42272a494951dc0f'
  - url: 'https://git.kernel.org/stable/c/23194531595c5d1d4454e3a607b0c8fc0c4e8695'
  - url: 'https://git.kernel.org/stable/c/5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.508Z'
---

## Overview

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

nvmet: copy the hostid into the ctrl before creating PR pc_refs

Commit 6202783184bf ("nvmet: Improve nvmet_alloc_ctrl() interface and
implementation") added a second uuid_copy() of args->hostid near the end
of nvmet_alloc_ctrl(), and commit 7b658153f1b8 ("nvmet: Remove duplicate
uuid_copy") removed the original copy that sat before
nvmet_ctrl_init_pr() instead of the new one.

Since then nvmet_ctrl_init_pr() snapshots ctrl->hostid into the
per-controller per-namespace reservation refs while the uuid_copy()
from the connect data runs later, after the controller is published.
The ctrl is allocated with kzalloc(), so every pc_ref created on this
path stores the nil UUID.

pc_ref->hostid has a single consumer: nvmet_pr_set_ctrl_to_abort()
matches it against the preempted registrant's hostid to kill and drain
the victim's in-flight I/O for Preempt and Abort.  The match can never
hit with the nil UUID, so whenever a namespace with reservations
enabled exists before a host connects, which includes every reconnect,
Preempt and Abort silently degrades into a plain Preempt: the
preempting host sees success while the victim's in-flight I/O is still
in the air.

Copy the hostid where the rest of the connect data is consumed, before
the controller is published and before nvmet_ctrl_init_pr() takes its
snapshot.

## Affected

- `Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd < d3d6d7efdacc08616d23b3ac42272a494951dc0f`
- `Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd < 23194531595c5d1d4454e3a607b0c8fc0c4e8695`
- `Linux >= 7b658153f1b8a79ed98980f2fef7b92a66aeb9cd < 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62`
- `Linux 6.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.