# CVE-2026-53125: md: fix array_state=clear sysfs deadlock

> A race condition in the Linux kernel md driver causes a deadlock when clearing array state, leading to denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** BELL-CVE-2026-53125, DEBIAN-CVE-2026-53125, GHSA-9m96-3qwq-4728, UBUNTU-CVE-2026-53125

## What is CVE-2026-53125?

CVE-2026-53125 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. 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: fix array_state=clear sysfs deadlock

When "clear" is written to array_state, md_attr_store() breaks sysfs
active protection so the array can delete itself from its own sysfs
store method.

However, md_attr_store() currently drops the mddev reference before
calling sysfs_unbreak_active_protection(). Once do_md_stop(..., 0)
has made the mddev eligible for delayed deletion, the temporary
kobject reference taken by sysfs_break_active_protection() can become
the last kobject reference protecting the md kobject.

That allows sysfs_unbreak_active_protection() to drop the last
kobject reference from the current sysfs writer context. kobject
teardown then recurses into kernfs removal while the current sysfs
node is still being unwound, and lockdep reports recursive locking on
kn->active with kernfs_drain() in the call chain.

Reproducer on an existing level:
1. Create an md0 linear array and activate it:
   mknod /dev/md0 b 9 0
   echo none > /sys/block/md0/md/metadata_version
   echo linear > /sys/block/md0/md/level
   echo 1 > /sys/block/md0/md/raid_disks
   echo "$(cat /sys/class/block/sdb/dev)" > /sys/block/md0/md/new_dev
   echo "$(($(cat /sys/class/block/sdb/size) / 2))" > \
	/sys/block/md0/md/dev-sdb/size
   echo 0 > /sys/block/md0/md/dev-sdb/slot
   echo active > /sys/block/md0/md/array_state
2. Wait briefly for the array to settle, then clear it:
   sleep 2
   echo clear > /sys/block/md0/md/array_state

The warning looks like:

  WARNING: possible recursive locking detected
  bash/588 is trying to acquire lock:
  (kn->active#65) at __kernfs_remove+0x157/0x1d0
  but task is already holding lock:
  (kn->active#65) at sysfs_unbreak_active_protection+0x1f/0x40
  ...
  Call Trace:
   kernfs_drain
   __kernfs_remove
   kernfs_remove_by_name_ns
   sysfs_remove_group
   sysfs_remove_groups
   __kobject_del
   kobject_put
   md_attr_store
   kernfs_fop_write_iter
   vfs_write
   ksys_write

Restore active protection before mddev_put() so the extra sysfs
kobject reference is dropped while the mddev is still held alive. The
actual md kobject deletion is then deferred until after the sysfs
write path has fully returned.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-53125?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53125?

Apply the vendor's patch.

## Is CVE-2026-53125 being exploited?

There is no known exploitation of CVE-2026-53125 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-2026-53125 and fix it if it is affected.

What it is: CVE-2026-53125 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. 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-2026-53125 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-2026-53125/ (Markdown: https://insights.sbomify.com/CVE-2026-53125/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53125
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53125
- OSV: https://osv.dev/vulnerability/CVE-2026-53125

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53125/
Summaries are generated and may contain mistakes; the official description above is the record.