---
id: CVE-2026-23148
title: 'nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference

  There is a race condition in nvmet_bio_done() that can cause a NULL
  pointer dereference in blk_…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 431e58d56fcb5ff1f9eb630724a922e0d2a941df <
    ee10b06980acca1d46e0fa36d6fb4a9578eab6e4
  - >-
    Linux >= 190f4c2c863af7cc5bb354b70e0805f06419c038 <
    68207ceefd71cc74ce4e983fa9bd10c3122e349b
  - >-
    Linux >= 190f4c2c863af7cc5bb354b70e0805f06419c038 <
    0fcee2cfc4b2e16e62ff8e0cc2cd8dd24efad65e
  - Linux 2e2028fcf924d1c6df017033c8d6e28b735a0508
  - Linux >= 6.12.37 < 6.12.69
  - Linux >= 6.15.6 < 6.16
  - Linux 6.16
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-16T15:06:34.978751Z'
published: '2026-02-14'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:09:49.729Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23148'
references:
  - url: 'https://git.kernel.org/stable/c/ee10b06980acca1d46e0fa36d6fb4a9578eab6e4'
  - url: 'https://git.kernel.org/stable/c/68207ceefd71cc74ce4e983fa9bd10c3122e349b'
  - url: 'https://git.kernel.org/stable/c/0fcee2cfc4b2e16e62ff8e0cc2cd8dd24efad65e'
tags:
  - cve.org
epss: 0.00317
epssPercentile: 0.23033
ingestedAt: '2026-10-16T17:24:46.639Z'
---

## Overview

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

nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference

There is a race condition in nvmet_bio_done() that can cause a NULL
pointer dereference in blk_cgroup_bio_start():

1. nvmet_bio_done() is called when a bio completes
2. nvmet_req_complete() is called, which invokes req->ops->queue_response(req)
3. The queue_response callback can re-queue and re-submit the same request
4. The re-submission reuses the same inline_bio from nvmet_req
5. Meanwhile, nvmet_req_bio_put() (called after nvmet_req_complete)
   invokes bio_uninit() for inline_bio, which sets bio->bi_blkg to NULL
6. The re-submitted bio enters submit_bio_noacct_nocheck()
7. blk_cgroup_bio_start() dereferences bio->bi_blkg, causing a crash:

  BUG: kernel NULL pointer dereference, address: 0000000000000028
  #PF: supervisor read access in kernel mode
  RIP: 0010:blk_cgroup_bio_start+0x10/0xd0
  Call Trace:
   submit_bio_noacct_nocheck+0x44/0x250
   nvmet_bdev_execute_rw+0x254/0x370 [nvmet]
   process_one_work+0x193/0x3c0
   worker_thread+0x281/0x3a0

Fix this by reordering nvmet_bio_done() to call nvmet_req_bio_put()
BEFORE nvmet_req_complete(). This ensures the bio is cleaned up before
the request can be re-submitted, preventing the race condition.

## Affected

- `Linux >= 431e58d56fcb5ff1f9eb630724a922e0d2a941df < ee10b06980acca1d46e0fa36d6fb4a9578eab6e4`
- `Linux >= 190f4c2c863af7cc5bb354b70e0805f06419c038 < 68207ceefd71cc74ce4e983fa9bd10c3122e349b`
- `Linux >= 190f4c2c863af7cc5bb354b70e0805f06419c038 < 0fcee2cfc4b2e16e62ff8e0cc2cd8dd24efad65e`
- `Linux 2e2028fcf924d1c6df017033c8d6e28b735a0508`
- `Linux >= 6.12.37 < 6.12.69`
- `Linux >= 6.15.6 < 6.16`
- `Linux 6.16`

## Remediation

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