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Linux KernelOperating system · Linux

CVE-2026-43340

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-08
Fix available
A fix is available. Upgrade to 5.10.253 / 5.15.203 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: comedi: Reinit dev->spinlock between attachments to low-level drivers `struct comedi_device` is the main controlling structure for a COMEDI device created by the COMEDI subsystem. It contains a member `spinlock` containing a spin-lock that is initialized by the COMEDI subsystem, but is reserved for use by a low-level driver attached to the COMEDI device (at least since commit 25436dc9d84f ("Staging: comedi: remove RT code")). Some COMEDI devices (those created on initialization of the COMEDI subsystem when the "comedi.comedi_num_legacy_minors" parameter is non-zero) can be attached to different low-level drivers over their lifetime using the `COMEDI_DEVCONFIG` ioctl command. This can result in inconsistent lock states being reported when there is a mismatch in the spin-lock locking levels used by each low-level driver to which the COMEDI device has been attached. Fix it by reinitializing `dev->spinlock` before calling the low-level driver's `attach` function pointer if `CONFIG_LOCKDEP` is enabled.

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

A detailed technical summary for this CVE is being prepared.

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:>= 2.6.29, < 5.10.253>= 5.11, < 5.15.203>= 5.16, < 6.1.168>= 6.2, < 6.6.134>= 6.7, < 6.12.81>= 6.13, < 6.18.22>= 6.19, < 6.19.12= 7.0

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 5.10.253 / 5.15.203 / 6.1.168 or later
Fixed in 5.10.2535.15.2036.1.168
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel 5.10.253 or later (5.10.x branch), 5.15.203 or later (5.15.x branch), 6.1.168 or later (6.1.x branch), or 6.6.134 or later (6.2.x-6.5.x branch)

  1. Identify your current Linux kernel version using `uname -r`
  2. Determine which branch your kernel version belongs to (e.g., 5.10.x, 5.15.x, 6.1.x, 6.2.x)
  3. Upgrade to a kernel version >= 5.10.253 (for 5.10.x), >= 5.15.203 (for 5.15.x), >= 6.1.168 (for 6.1.x), or >= 6.6.134 (for 6.2.x through 6.5.x)
  4. Reboot into the upgraded kernel
  5. Verify the fix is applied by checking the kernel version and confirming the comedi module loads correctly
Caveat Kernel upgrades may require updates to out-of-tree modules or kernel drivers; ensure compatibility with existing system configurations before upgrading

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-2026-43340 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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