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Linux KernelOperating system · Linux

CVE-2025-38650

MEDIUM · 5.5 CVSS v3.1 Published 2025-08-22
Fix available
A fix is available. Upgrade to 5.4.297 / 5.10.241 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-667

Shared resources are accessed without correct locking, so concurrent operations interleave into inconsistent — and sometimes exploitable — states, or deadlock the service outright. These bugs are subtle and timing-dependent. The fix is correct, consistent locking or atomic operations around every shared resource.

General guidance for the improper locking class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.19, < 5.4.297>= 5.5, < 5.10.241>= 5.11, < 5.15.190>= 5.16, < 6.1.148>= 6.2, < 6.6.102>= 6.7, < 6.12.42>= 6.13, < 6.15.10>= 6.16, < 6.16.1
Debian LinuxOperating system
Affected:= 11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.297 / 5.10.241 / 5.15.190 or later
Fixed in 5.4.2975.10.2415.15.190
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 6.1.148 (or latest stable 6.1.y release)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Check if the running kernel version is within the affected ranges: >= 4.19 and < 5.4.297, >= 5.5 and < 5.10.241, >= 5.11 and < 5.15.190, or >= 5.16 and < 6.1.148
  3. For Debian 11.0 systems, check kernel version with `uname -r` and verify if it is affected
  4. Upgrade the Linux kernel to a fixed release: 5.4.297 or later for the 5.4.y branch, 5.10.241 or later for the 5.10.y branch, 5.15.190 or later for the 5.15.y branch, or 6.1.148 or later for the 6.1.y branch
  5. Apply the vendor patch from commit 0807e4ac59a546f2346961c5e26a98901594b205 if upgrading is not immediately feasible
  6. Reboot the system into the updated kernel to apply the fix
  7. Verify the fix is applied by checking that the WARN_ON in hfsplus_free_extents no longer triggers under concurrent access scenarios
Caveat Kernel upgrades may introduce changes to other subsystems; ensure compatibility with existing system configuration and drivers before deploying in production

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-38650 in production — separate from our analysis above.

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What this is

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