# CVE-2026-23148: nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference

> A race condition in the Linux kernel's nvmet module causes a NULL pointer dereference, leading to a system crash.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Feb 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-23148, DEBIAN-CVE-2026-23148, GHSA-c783-64qq-77vx, ROOT-OS-UBUNTU-2404-CVE-2026-23148, UBUNTU-CVE-2026-23148

## What is CVE-2026-23148?

CVE-2026-23148 is a high-severity vulnerability in Linux kernel, published on 14 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-23148?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23148?

Apply the vendor's patch.

## Is CVE-2026-23148 being exploited?

There is no known exploitation of CVE-2026-23148 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23148 and fix it if it is affected.

What it is: CVE-2026-23148 is a high-severity vulnerability in Linux kernel, published on 14 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23148 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23148/ (Markdown: https://insights.sbomify.com/CVE-2026-23148/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23148
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23148
- OSV: https://osv.dev/vulnerability/CVE-2026-23148

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23148/
Summaries are generated and may contain mistakes; the official description above is the record.