CVE-2026-72156: fpga: microchip-spi: fix zero header_size OOB read in mpf_ops_parse_header()

CVE-2026-72156: fpga: microchip-spi: fix zero header_size OOB read in mpf_ops_parse_header()

[Greg Kroah-Hartman]

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

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

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

fpga: microchip-spi: fix zero header_size OOB read in mpf_ops_parse_header()

mpf_ops_parse_header() reads header_size from the bitstream at
MPF_HEADER_SIZE_OFFSET (24). When header_size is zero, the expression
*(buf + header_size - 1) reads one byte before the buffer start.

Since initial_header_size is set to 71 in mpf_ops, the fpga-mgr core
guarantees the buffer is large enough to reach MPF_HEADER_SIZE_OFFSET.
The only real gap is the zero header_size case, which cannot be
resolved by providing a larger buffer, so return -EINVAL.

The Linux kernel CVE team has assigned CVE-2026-72156 to this issue.


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

	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 6.1.178 with commit e45ec24d8e986d79a8e07f49a816c414ad283622
	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 6.6.145 with commit 0d3766fecd9b2db39a18b48021c15c522997ec25
	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 6.12.97 with commit a1baee24df72ec8fd1d6925c1d5162ffff4ee3bf
	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 6.18.40 with commit c9ef79e34bc1eac4fd59051e5c7b96a74e59d46f
	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 7.1.5 with commit 3da8eaf5469eda2353b72038d644fabddb848ce1
	Issue introduced in 6.0 with commit 5f8d4a9008307e0bf210906948953386935d361c and fixed in 7.2-rc1 with commit 43a1974da6bc7ce8f4d1dc1d03d56997428c29c3

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-2026-72156
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/fpga/microchip-spi.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/e45ec24d8e986d79a8e07f49a816c414ad283622
	https://git.kernel.org/stable/c/0d3766fecd9b2db39a18b48021c15c522997ec25
	https://git.kernel.org/stable/c/a1baee24df72ec8fd1d6925c1d5162ffff4ee3bf
	https://git.kernel.org/stable/c/c9ef79e34bc1eac4fd59051e5c7b96a74e59d46f
	https://git.kernel.org/stable/c/3da8eaf5469eda2353b72038d644fabddb848ce1
	https://git.kernel.org/stable/c/43a1974da6bc7ce8f4d1dc1d03d56997428c29c3