# CVE-2025-38650: hfsplus: remove mutex_lock check in hfsplus_free_extents

> A race condition in the Linux kernel HFS+ filesystem triggers a warning during concurrent file operations, potentially causing system instability or 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:** 22 Aug 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-66620, BELL-CVE-2025-38650, DEBIAN-CVE-2025-38650, GHSA-x465-6xx8-6h3c, ROOT-OS-DEBIAN-11-CVE-2025-38650, ROOT-OS-DEBIAN-12-CVE-2025-38650, ROOT-OS-DEBIAN-13-CVE-2025-38650, ROOT-OS-UBUNTU-2204-CVE-2025-38650, ROOT-OS-UBUNTU-2404-CVE-2025-38650, UBUNTU-CVE-2025-38650

## What is CVE-2025-38650?

CVE-2025-38650 is a medium-severity vulnerability in Debian Debian Linux, published on 22 Aug 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:

hfsplus: remove mutex_lock check in hfsplus_free_extents

Syzbot reported an issue in hfsplus filesystem:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 4400 at fs/hfsplus/extents.c:346
	hfsplus_free_extents+0x700/0xad0
Call Trace:
<TASK>
hfsplus_file_truncate+0x768/0xbb0 fs/hfsplus/extents.c:606
hfsplus_write_begin+0xc2/0xd0 fs/hfsplus/inode.c:56
cont_expand_zero fs/buffer.c:2383 [inline]
cont_write_begin+0x2cf/0x860 fs/buffer.c:2446
hfsplus_write_begin+0x86/0xd0 fs/hfsplus/inode.c:52
generic_cont_expand_simple+0x151/0x250 fs/buffer.c:2347
hfsplus_setattr+0x168/0x280 fs/hfsplus/inode.c:263
notify_change+0xe38/0x10f0 fs/attr.c:420
do_truncate+0x1fb/0x2e0 fs/open.c:65
do_sys_ftruncate+0x2eb/0x380 fs/open.c:193
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

To avoid deadlock, Commit 31651c607151 ("hfsplus: avoid deadlock
on file truncation") unlock extree before hfsplus_free_extents(),
and add check wheather extree is locked in hfsplus_free_extents().

However, when operations such as hfsplus_file_release,
hfsplus_setattr, hfsplus_unlink, and hfsplus_get_block are executed
concurrently in different files, it is very likely to trigger the
WARN_ON, which will lead syzbot and xfstest to consider it as an
abnormality.

The comment above this warning also describes one of the easy
triggering situations, which can easily trigger and cause
xfstest&syzbot to report errors.

[task A]			[task B]
->hfsplus_file_release
  ->hfsplus_file_truncate
    ->hfs_find_init
      ->mutex_lock
    ->mutex_unlock
				->hfsplus_write_begin
				  ->hfsplus_get_block
				    ->hfsplus_file_extend
				      ->hfsplus_ext_read_extent
				        ->hfs_find_init
					  ->mutex_lock
    ->hfsplus_free_extents
      WARN_ON(mutex_is_locked) !!!

Several threads could try to lock the shared extents tree.
And warning can be triggered in one thread when another thread
has locked the tree. This is the wrong behavior of the code and
we need to remove the warning.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2025-38650?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38650?

Apply the vendor's patch.

## Is CVE-2025-38650 being exploited?

There is no known exploitation of CVE-2025-38650 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38650 and fix it if it is affected.

What it is: CVE-2025-38650 is a medium-severity vulnerability in Debian Debian Linux, published on 22 Aug 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-2025-38650 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-38650/ (Markdown: https://insights.sbomify.com/CVE-2025-38650/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38650
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38650
- OSV: https://osv.dev/vulnerability/CVE-2025-38650

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38650/
Summaries are generated and may contain mistakes; the official description above is the record.