CVE-2026-31751

comedi: dt2815: add hardware detection to prevent crash

State: Published
Severity: Not scored
Published: May 1, 2026
Updated: May 11, 2026
Reserved: Mar 9, 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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	d6a929b7608ae157cef86d00cc580d1038f0b985 to before 8d63161837f1bf8810dbcd2a583c2bbf5ca6d733Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before d2a786efdb9971f2a647724625da5bbecc994dc9Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before 0dcf33994b8dcf3db36530fb7e2cf9f89e5cbac3Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before d5d9df8b08d68d083ac57abc2c887dfb1f31af63Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before 65c528fbeddd88478c210052f6c7b21be4973156Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before 34c8b3a91bdfbe4573650b4cd750ef639101fdc5Affected d6a929b7608ae157cef86d00cc580d1038f0b985 to before 34b13250c618d7441508c6ef369144aa8a9b9bfaAffected d6a929b7608ae157cef86d00cc580d1038f0b985 to before 93853512f565e625df2397f0d8050d6aafd7c3adAffected
LinuxLinux	2.6.30Affected before 2.6.30Not affected 5.10.253 through 5.10.Not affected 5.15.203 through 5.15.Not affected 6.1.168 through 6.1.Not affected 6.6.134 through 6.6.Not affected 6.12.81 through 6.12.Not affected 6.18.22 through 6.18.Not affected 6.19.12 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

d6a929b7608ae157cef86d00cc580d1038f0b985 to before 8d63161837f1bf8810dbcd2a583c2bbf5ca6d733Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before d2a786efdb9971f2a647724625da5bbecc994dc9Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before 0dcf33994b8dcf3db36530fb7e2cf9f89e5cbac3Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before d5d9df8b08d68d083ac57abc2c887dfb1f31af63Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before 65c528fbeddd88478c210052f6c7b21be4973156Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before 34c8b3a91bdfbe4573650b4cd750ef639101fdc5Affected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before 34b13250c618d7441508c6ef369144aa8a9b9bfaAffected
d6a929b7608ae157cef86d00cc580d1038f0b985 to before 93853512f565e625df2397f0d8050d6aafd7c3adAffected

LinuxLinux

2.6.30Affected
before 2.6.30Not affected
5.10.253 through 5.10.*Not affected
5.15.203 through 5.15.*Not affected
6.1.168 through 6.1.*Not affected
6.6.134 through 6.6.*Not affected
6.12.81 through 6.12.*Not affected
6.18.22 through 6.18.*Not affected
6.19.12 through 6.19.*Not affected
7.0 and laterNot affected

References

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