CVE-2026-31751 comedi: dt2815: add hardware detection to prevent crash
A race condition in the dt2815 driver allows local attackers to crash the system by attaching to non-existent hardware ports.
- 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
What is CVE-2026-31751?
CVE-2026-31751 is a medium-severity vulnerability in Linux kernel, published on 1 May 2026. 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:
comedi: dt2815: add hardware detection to prevent crash
The dt2815 driver crashes when attached to I/O ports without actual hardware present. This occurs because syzkaller or users can attach the driver to arbitrary I/O addresses via COMEDI_DEVCONFIG ioctl.
When no hardware exists at the specified port, inb() operations return 0xff (floating bus), but outb() operations can trigger page faults due to undefined behavior, especially under race conditions:
BUG: unable to handle page fault for address: 000000007fffff90 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page RIP: 0010:dt2815_attach+0x6e0/0x1110
Add hardware detection by reading the status register before attempting any write operations. If the read returns 0xff, assume no hardware is present and fail the attach with -ENODEV. This prevents crashes from outb() operations on non-existent hardware.
Weakness: CWE-362
Which versions are affected by CVE-2026-31751?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31751?
Apply the vendor's patch.
Is CVE-2026-31751 being exploited?
There is no known exploitation of CVE-2026-31751 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31751, DEBIAN-CVE-2026-31751, GHSA-6g9c-277p-7xw6, ROOT-OS-DEBIAN-11-CVE-2026-31751, ROOT-OS-UBUNTU-2204-CVE-2026-31751, ROOT-OS-UBUNTU-2404-CVE-2026-31751 and 1 more.