CVE-2026-68340: hwmon: occ: validate poll response sensor blocks

From: Greg Kroah-Hartman <[email protected]>

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

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

hwmon: occ: validate poll response sensor blocks

The OCC poll response parser walks a counted list of sensor data blocks.
It used the static backing-array capacity as the parse boundary, but a
transport response makes only data_length bytes current and valid. A
truncated response can therefore make the parser consume a block header or
block extent outside the current response.

Use data_length as the parent boundary, prove the fixed poll header and
each current block header before reading them, and prove the complete block
before advancing. Keep parsed sensor metadata local until the complete
response has passed validation, then publish it. Propagate
malformed-response errors before publishing the OCC as active.

The Linux kernel CVE team has assigned CVE-2026-68340 to this issue.


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

	Issue introduced in 5.0 with commit aa195fe49b033db545ad986cdb2c431c37bea557 and fixed in 6.6.148 with commit 112525534ab5cff482d35897ca4ca11fd3a76f46
	Issue introduced in 5.0 with commit aa195fe49b033db545ad986cdb2c431c37bea557 and fixed in 6.12.101 with commit 54cb78eceb4e286ccd5a5c01a4632157860d47f0
	Issue introduced in 5.0 with commit aa195fe49b033db545ad986cdb2c431c37bea557 and fixed in 6.18.42 with commit 538d862cc0dbd5c732fe26d5aad98eae039e6676
	Issue introduced in 5.0 with commit aa195fe49b033db545ad986cdb2c431c37bea557 and fixed in 7.1.6 with commit b042e538e98b939fccfffc464e2c34c29f0e96ef
	Issue introduced in 5.0 with commit aa195fe49b033db545ad986cdb2c431c37bea557 and fixed in 7.2-rc5 with commit 70e76e700fc6c46afb4e17aec099a1ea089b4a22

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-2026-68340
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/hwmon/occ/common.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/112525534ab5cff482d35897ca4ca11fd3a76f46
	https://git.kernel.org/stable/c/54cb78eceb4e286ccd5a5c01a4632157860d47f0
	https://git.kernel.org/stable/c/538d862cc0dbd5c732fe26d5aad98eae039e6676
	https://git.kernel.org/stable/c/b042e538e98b939fccfffc464e2c34c29f0e96ef
	https://git.kernel.org/stable/c/70e76e700fc6c46afb4e17aec099a1ea089b4a22