# CVE-2026-31749: comedi: ni\_atmio16d: Fix invalid clean-up after failed attach

- 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: ni_atmio16d: Fix invalid clean-up after failed attach If the driver's COMEDI "attach" handler function (`atmio16d_attach()`) returns an error, the COMEDI core will call the driver's "detach" handler function (`atmio16d_detach()`) to clean up. This calls `reset_atmio16d()` unconditionally, but depending on where the error occurred in the attach handler, the device may not have been sufficiently initialized to call `reset_atmio16d()`. It uses `dev->iobase` as the I/O port base address and `dev->private` as the pointer to the COMEDI device's private data structure. `dev->iobase` may still be set to its initial value of 0, which would result in undesired writes to low I/O port addresses. `dev->private` may still be `NULL`, which would result in null pointer dereferences. Fix `atmio16d_detach()` by checking that `dev->private` is valid (non-null) before calling `reset_atmio16d()`. This implies that `dev->iobase` was set correctly since that is set up before `dev->private`.

## 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.
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## 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/a01dd339ea6ac58b0967a50085622a6017351140
- https://git.kernel.org/stable/c/933a2d6a95f9bfb203e562c9be1dd990c735535c
- https://git.kernel.org/stable/c/5d8d88c8c0eec230de8f1f60e0920a4337939a88
- https://git.kernel.org/stable/c/f517646e008fe99ca1800601cd011b110f8684ae
- https://git.kernel.org/stable/c/3848ae00b1642e2c98ff8cbfd2d3b38c6f53b5c3
- https://git.kernel.org/stable/c/43c68a2c7cc35b7c2a83c285cb4ad3d472b8caa2
- https://git.kernel.org/stable/c/d07d97ca4f7fac467cdcf4a012690853958b7e89
- https://git.kernel.org/stable/c/101ab946b79ad83b36d5cfd47de587492a80acf0

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Page: https://cve.now/CVE-2026-31749
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