CVE-2026-74458: can: kvaser_usb_leaf: kvaser_usb_leaf_wait_cmd(): validate received command extents

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

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

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

can: kvaser_usb_leaf: kvaser_usb_leaf_wait_cmd(): validate received command extents

The wait and bulk receive paths walk variable-length commands from a
USB buffer. A nonzero command shorter than CMD_HEADER_LEN can still be
dispatched, and the wait path copies a matching command into a fixed
caller-owned struct kvaser_cmd using the device-provided length.

Reject nonzero commands that do not contain the fixed header or that
extend beyond the current USB buffer item. In the wait path, also reject
a matching command that exceeds the destination before copying it.

The Linux kernel CVE team has assigned CVE-2026-74458 to this issue.


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

	Issue introduced in 3.8 with commit 080f40a6fa28dab299da7a652e444b1e2d9231e7 and fixed in 6.6.151 with commit 695aea154bb2d453e6daada1510972fafd075285
	Issue introduced in 3.8 with commit 080f40a6fa28dab299da7a652e444b1e2d9231e7 and fixed in 6.12.103 with commit 3d0897ec623e422695d70d80ae456f89476c5328
	Issue introduced in 3.8 with commit 080f40a6fa28dab299da7a652e444b1e2d9231e7 and fixed in 6.18.44 with commit 185cb1fa38142a3cbf223dd8b3abb24217f330d3
	Issue introduced in 3.8 with commit 080f40a6fa28dab299da7a652e444b1e2d9231e7 and fixed in 7.1.8 with commit 21f0465fd86d77794aaed8e05f833634f68d178d
	Issue introduced in 3.8 with commit 080f40a6fa28dab299da7a652e444b1e2d9231e7 and fixed in 7.2-rc6 with commit 0293dd153f9dbc1ddf5dacdccc76b363bce4a8ee

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-2026-74458
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/net/can/usb/kvaser_usb/kvaser_usb_leaf.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/695aea154bb2d453e6daada1510972fafd075285
	https://git.kernel.org/stable/c/3d0897ec623e422695d70d80ae456f89476c5328
	https://git.kernel.org/stable/c/185cb1fa38142a3cbf223dd8b3abb24217f330d3
	https://git.kernel.org/stable/c/21f0465fd86d77794aaed8e05f833634f68d178d
	https://git.kernel.org/stable/c/0293dd153f9dbc1ddf5dacdccc76b363bce4a8ee