CVE-2026-31751
Published: May 6, 2026Last modified: May 6, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 4.7 |
| Attack Vector | LOCAL |
| Attack complexity | HIGH |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.168-r0) |
| 25 LTS | linux-lts | Fixed (6.12.81-r0) | |
| Stream | linux-lts | Fixed (6.12.85-r0) |
References
- https://git.kernel.org/stable/c/0dcf33994b8dcf3db36530fb7e2cf9f89e5cbac3
- https://git.kernel.org/stable/c/34b13250c618d7441508c6ef369144aa8a9b9bfa
- https://git.kernel.org/stable/c/34c8b3a91bdfbe4573650b4cd750ef639101fdc5
- https://git.kernel.org/stable/c/65c528fbeddd88478c210052f6c7b21be4973156
- https://git.kernel.org/stable/c/8d63161837f1bf8810dbcd2a583c2bbf5ca6d733
- https://git.kernel.org/stable/c/93853512f565e625df2397f0d8050d6aafd7c3ad
- https://git.kernel.org/stable/c/d2a786efdb9971f2a647724625da5bbecc994dc9
- https://git.kernel.org/stable/c/d5d9df8b08d68d083ac57abc2c887dfb1f31af63