CVE-2026-64087: hwmon: (pmbus/adm1266) reject implausible blackbox record_count

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

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

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

hwmon: (pmbus/adm1266) reject implausible blackbox record_count

adm1266_nvmem_read_blackbox() loops over a record_count that comes
straight from byte 3 of the BLACKBOX_INFO response.  The destination
buffer is data->dev_mem, sized for the nvmem cell's declared 2048
bytes (ADM1266_BLACKBOX_MAX_RECORDS * ADM1266_BLACKBOX_SIZE = 32 * 64).
A device that reports a record_count greater than 32 -- whether due
to firmware bugs, bus corruption, or a non-responsive slave returning
0xff -- would walk read_buff past the end of the dev_mem allocation
on the trailing iterations.

Cap record_count at ADM1266_BLACKBOX_MAX_RECORDS (introduced here)
before entering the loop and return -EIO on any larger value, so a
malformed BLACKBOX_INFO response cannot drive the loop out of bounds.

The Linux kernel CVE team has assigned CVE-2026-64087 to this issue.


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

	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 5.10.258 with commit adcb163ad7cacca317872fc62bd8885e842e45e3
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 5.15.209 with commit c2c56092710fe8a893b67b5a3d7e62808d02d84d
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 6.1.175 with commit 5469e1e7c411acc15fdd8262c99c3ebd9defd594
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 6.6.142 with commit f85c81e93dbd6915970bd5f3bffcf62633c4c54c
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 6.12.92 with commit 0e791cd0140fb136083565aadfbe0f705aa260d0
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 6.18.34 with commit 75c862adf3d3caab4f49bb3530723c215376e37c
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 7.0.11 with commit 231db52a5b64d0a9769e298dadc148e1f79b26a6
	Issue introduced in 5.10 with commit 15609d1893020436e1e8ccfd9ded774a96dd17a2 and fixed in 7.1 with commit 4afca954622d672ea65ed961bed01cf91caa034e

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-2026-64087
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/pmbus/adm1266.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/adcb163ad7cacca317872fc62bd8885e842e45e3
	https://git.kernel.org/stable/c/c2c56092710fe8a893b67b5a3d7e62808d02d84d
	https://git.kernel.org/stable/c/5469e1e7c411acc15fdd8262c99c3ebd9defd594
	https://git.kernel.org/stable/c/f85c81e93dbd6915970bd5f3bffcf62633c4c54c
	https://git.kernel.org/stable/c/0e791cd0140fb136083565aadfbe0f705aa260d0
	https://git.kernel.org/stable/c/75c862adf3d3caab4f49bb3530723c215376e37c
	https://git.kernel.org/stable/c/231db52a5b64d0a9769e298dadc148e1f79b26a6
	https://git.kernel.org/stable/c/4afca954622d672ea65ed961bed01cf91caa034e