CVE-2026-68089: iio: core: fix uninitialized data in debugfs

CVE-2026-68089: iio: core: fix uninitialized data in debugfs

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

iio: core: fix uninitialized data in debugfs

If *ppos is non-zero then simple_write_to_buffer() will not initialize
the start of buf[].  Non zero values for *ppos aren't going to work
anyway.  Test for them at the start of the function and return -EINVAL.

The Linux kernel CVE team has assigned CVE-2026-68089 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.15 with commit 6d5dd486c715908b5a6ed02315a15ff044a91025 and fixed in 6.18.39 with commit e166a8cfb28a3d0da260dd70cae274eb8c7cec8d
	Issue introduced in 6.15 with commit 6d5dd486c715908b5a6ed02315a15ff044a91025 and fixed in 7.1.4 with commit 89fbd3e32dffb6227f936a9578e6eb4632aa4580
	Issue introduced in 6.15 with commit 6d5dd486c715908b5a6ed02315a15ff044a91025 and fixed in 7.2-rc1 with commit ab92ed206d41fd171ebd37bc46360d9f2140d043

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68089
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/iio/industrialio-core.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/e166a8cfb28a3d0da260dd70cae274eb8c7cec8d
	https://git.kernel.org/stable/c/89fbd3e32dffb6227f936a9578e6eb4632aa4580
	https://git.kernel.org/stable/c/ab92ed206d41fd171ebd37bc46360d9f2140d043