linux-cve-announce - CVE-2025-68773: spi: fsl-cpm: Check length parity before switching to 16 bit mode

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Message-ID: <2026011358-CVE-2025-68773-bd5d@gregkh>
Date: Tue, 13 Jan 2026 16:28:59 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68773: spi: fsl-cpm: Check length parity before switching to 16 bit mode

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

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

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

spi: fsl-cpm: Check length parity before switching to 16 bit mode

Commit fc96ec826bce ("spi: fsl-cpm: Use 16 bit mode for large transfers
with even size") failed to make sure that the size is really even
before switching to 16 bit mode. Until recently the problem went
unnoticed because kernfs uses a pre-allocated bounce buffer of size
PAGE_SIZE for reading EEPROM.

But commit 8ad6249c51d0 ("eeprom: at25: convert to spi-mem API")
introduced an additional dynamically allocated bounce buffer whose size
is exactly the size of the transfer, leading to a buffer overrun in
the fsl-cpm driver when that size is odd.

Add the missing length parity verification and remain in 8 bit mode
when the length is not even.

The Linux kernel CVE team has assigned CVE-2025-68773 to this issue.


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

	Issue introduced in 6.1.29 with commit 7f6738e003b364783f3019fdf6e7645bc8dd1643 and fixed in 6.1.160 with commit 837a23a11e0f734f096c7c7b0778d0e625e3dc87
	Issue introduced in 6.4 with commit fc96ec826bced75cc6b9c07a4ac44bbf651337ab and fixed in 6.6.120 with commit 3dd6d01384823e1bd8602873153d6fc4337ac4fe
	Issue introduced in 6.4 with commit fc96ec826bced75cc6b9c07a4ac44bbf651337ab and fixed in 6.12.64 with commit 743cebcbd1b2609ec5057ab474979cef73d1b681
	Issue introduced in 6.4 with commit fc96ec826bced75cc6b9c07a4ac44bbf651337ab and fixed in 6.18.3 with commit be0b613198e6bfa104ad520397cab82ad3ec1771
	Issue introduced in 6.4 with commit fc96ec826bced75cc6b9c07a4ac44bbf651337ab and fixed in 6.19-rc2 with commit 1417927df8049a0194933861e9b098669a95c762
	Issue introduced in 4.14.316 with commit 42c04316d9275ec267d36e5e9064cd56c9884148
	Issue introduced in 4.19.284 with commit dc120f2d35b030390a2bc0f94dd5f37e900cae91
	Issue introduced in 5.4.244 with commit b558275c1b040f0e5aa56c862241f9212b6118c3
	Issue introduced in 5.10.181 with commit 60afe299bb541a928ba39bcb4ae8d3e428d1c5a5
	Issue introduced in 5.15.114 with commit 4badd33929c05ed314794b95f1af1308f7222be8
	Issue introduced in 6.2.16 with commit b9d9e8856f1c83e4277403f9b4c369b322ebcb12
	Issue introduced in 6.3.3 with commit 36a6d0f66c874666caf4e8be155b1be30f6231be

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-2025-68773
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/spi/spi-fsl-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/837a23a11e0f734f096c7c7b0778d0e625e3dc87
	https://git.kernel.org/stable/c/3dd6d01384823e1bd8602873153d6fc4337ac4fe
	https://git.kernel.org/stable/c/743cebcbd1b2609ec5057ab474979cef73d1b681
	https://git.kernel.org/stable/c/be0b613198e6bfa104ad520397cab82ad3ec1771
	https://git.kernel.org/stable/c/1417927df8049a0194933861e9b098669a95c762