CVE-2026-68182: comedi: comedi_parport: deal with premature interrupt
In the Linux kernel, the following vulnerability has been resolved:
comedi: comediparport: deal with premature interrupt
Syzbot reported a general protection fault in comedigetissubdevicerunning(), which was called from the interrupt handler parportinterrupt() in the "comediparport" driver, but it does not currently have a C reproducer for the problem. It's probably due to a premature interrupt for one of two reasons:
1. The driver sets up the interrupt handler before the comedi subdevices used by the interrupt handler have been allocated, but does not disable the interrupt in the parallel port's CTRL register first. 2. The driver uses a user-supplied I/O port base address which Syzbot would have supplied, but it might not be backed by real parallel port hardware.
Change the initialization order in the driver's comedi "attach" handler (parportattach()) so that the hardware registers are initialized before the interrupt handler is requested. This should prevent premature interrupts occurring for real hardware.
Also add a test to the interrupt handler to ensure the comedi device is fully attached and return early if it isn't.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
In the comedi "attach" handler, disable the interrupt in the parallel port's CTRL register first, then set up/request the interrupt handler only after the comedi device is fully attached (return early if it isn't).
comedi_parport driver parallel port CTRL register interrupt state = disable interrupt before requesting the interrupt handler - Configuration
Change the initialization order in the comedi "attach" handler so the driver sets up the interrupt handler only after the comedi subdevices are initialized/available, ensuring `comedi_get_is_subdevice_running()` called from `parport_interrupt()` is safe.
comedi_parport driver initialization order = request interrupt handler after comedi subdevices are set up
Event History
Frequently Asked Questions
What is the severity of CVE-2026-68182?
The severity of CVE-2026-68182 is rated at 27.
How do I fix CVE-2026-68182?
To fix CVE-2026-68182, update your Linux kernel to the patched version provided by the maintainers.
What systems are affected by CVE-2026-68182?
CVE-2026-68182 affects the Linux kernel that utilizes the comedi_parport driver.
What are the potential impacts of CVE-2026-68182?
The potential impacts of CVE-2026-68182 include a general protection fault that may lead to system instability.
Is there a workaround for CVE-2026-68182 until a fix is applied?
Currently, there are no specific workarounds documented for CVE-2026-68182, and immediate updating is recommended.