CVE-2026-17523: can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet

CVE-2026-17523: can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet

[Greg Kroah-Hartman]

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

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

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

can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet

This patch switches the timer to HRTIMER_MODE_SOFT, which executed the
timer callback in softirq context and removes the hrtimer_tasklet.

The Linux kernel CVE team has assigned CVE-2026-17523 to this issue.


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

	Fixed in 4.19.226 with commit 79305a826f872fe446c6fbf8450f515053ef6951
	Fixed in 5.4 with commit bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68

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-2026-17523
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:
	net/can/bcm.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/79305a826f872fe446c6fbf8450f515053ef6951
	https://git.kernel.org/stable/c/bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68