CVE-2025-38478

Technical Description

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

comedi: Fix initialization of data for instructions that write to subdevice

Some Comedi subdevice instruction handlers are known to access

instruction data elements beyond the first `insn->n` elements in some

cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions

allocate at least `MIN_SAMPLES` (16) data elements to deal with this,

but they do not initialize all of that. For Comedi instruction codes

that write to the subdevice, the first `insn->n` data elements are

copied from user-space, but the remaining elements are left

uninitialized. That could be a problem if the subdevice instruction

handler reads the uninitialized data. Ensure that the first

`MIN_SAMPLES` elements are initialized before calling these instruction

handlers, filling the uncopied elements with 0. For

`do_insnlist_ioctl()`, the same data buffer elements are used for

handling a list of instructions, so ensure the first `MIN_SAMPLES`

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References