# CVE-2025-68368: md: init bioset in mddev_init

> A local attacker with high privileges can trigger a kernel NULL pointer dereference in the md driver, causing a system crash.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2025-68368, DEBIAN-CVE-2025-68368, GHSA-8jvw-6j3w-p767, ROOT-OS-DEBIAN-13-CVE-2025-68368, UBUNTU-CVE-2025-68368

## What is CVE-2025-68368?

CVE-2025-68368 is a vulnerability in Linux, published on 24 Dec 2025. 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:

md: init bioset in mddev_init

IO operations may be needed before md_run(), such as updating metadata
after writing sysfs. Without bioset, this triggers a NULL pointer
dereference as below:

 BUG: kernel NULL pointer dereference, address: 0000000000000020
 Call Trace:
  md_update_sb+0x658/0xe00
  new_level_store+0xc5/0x120
  md_attr_store+0xc9/0x1e0
  sysfs_kf_write+0x6f/0xa0
  kernfs_fop_write_iter+0x141/0x2a0
  vfs_write+0x1fc/0x5a0
  ksys_write+0x79/0x180
  __x64_sys_write+0x1d/0x30
  x64_sys_call+0x2818/0x2880
  do_syscall_64+0xa9/0x580
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

Reproducer
```
  mdadm -CR /dev/md0 -l1 -n2 /dev/sd[cd]
  echo inactive > /sys/block/md0/md/array_state
  echo 10 > /sys/block/md0/md/new_level
```

mddev_init() can only be called once per mddev, no need to test if bioset
has been initialized anymore.

## Which versions are affected by CVE-2025-68368?


## How do I fix CVE-2025-68368?

Apply the vendor's patch.

## Is CVE-2025-68368 being exploited?

There is no known exploitation of CVE-2025-68368 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68368 and fix it if it is affected.

What it is: CVE-2025-68368 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68368 in the wild and no public exploit code.

Affected product: Linux. 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-2025-68368/ (Markdown: https://insights.sbomify.com/CVE-2025-68368/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68368
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68368
- OSV: https://osv.dev/vulnerability/CVE-2025-68368

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68368/
Summaries are generated and may contain mistakes; the official description above is the record.