CVE-2026-31749

In the Linux kernel, the following vulnerability has been resolved:

comedi: ni_atmio16d: Fix invalid clean-up after failed attach

If the drivers COMEDI attach handler function (atmio16d_attach()) returns an error, the COMEDI core will call the drivers 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 devices 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.

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

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