CVE-2026-43340: comedi: Reinit dev->spinlock between attachments to low-level drivers
In the Linux kernel, the following vulnerability has been resolved:
comedi: Reinit dev->spinlock between attachments to low-level drivers
struct comedidevice 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.comedinumlegacyminors" parameter is non-zero) can be attached to different low-level drivers over their lifetime using the COMEDIDEVCONFIG 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 CONFIGLOCKDEP is enabled.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43340?
CVE-2026-43340 has a medium severity rating due to potential race conditions affecting COMEDI devices.
How can I mitigate CVE-2026-43340?
Mitigation for CVE-2026-43340 involves updating to a patched version of the Linux kernel that resolves the spinlock reinitialization issue.
What are the potential impacts of CVE-2026-43340?
CVE-2026-43340 may lead to instability and unpredictable behavior in applications utilizing COMEDI devices.
Is CVE-2026-43340 remotely exploitable?
CVE-2026-43340 is not considered remotely exploitable as it requires local access to the affected system.
Which versions of the Linux kernel are affected by CVE-2026-43340?
CVE-2026-43340 affects specific versions of the Linux kernel that include the vulnerable handling of COMEDI devices.