CVE-2026-72114: can: bcm: validate frame length in bcm_rx_setup() for RTR replies

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

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

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

can: bcm: validate frame length in bcm_rx_setup() for RTR replies

bcm_tx_setup() validates cf->len against the CAN/CAN FD DLC limits
before installing frames for TX_SETUP, but bcm_rx_setup() never did
the same for the RTR-reply frame configured via RX_SETUP with
RX_RTR_FRAME.

The Linux kernel CVE team has assigned CVE-2026-72114 to this issue.


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

	Issue introduced in 2.6.25 with commit ffd980f976e7fd666c2e61bf8ab35107efd11828 and fixed in 6.6.148 with commit 7d966cdee006911d3957e1a4e72cb93c39cd8c1e
	Issue introduced in 2.6.25 with commit ffd980f976e7fd666c2e61bf8ab35107efd11828 and fixed in 6.12.101 with commit 1b475c0c72f44622a320a4386ce9e76f85e69bc7
	Issue introduced in 2.6.25 with commit ffd980f976e7fd666c2e61bf8ab35107efd11828 and fixed in 6.18.42 with commit deb6a697cce3f021e731df543597f37a5e54caab
	Issue introduced in 2.6.25 with commit ffd980f976e7fd666c2e61bf8ab35107efd11828 and fixed in 7.1.5 with commit 59bfddea64159594feb62ef11b7d7a33c8ee3783
	Issue introduced in 2.6.25 with commit ffd980f976e7fd666c2e61bf8ab35107efd11828 and fixed in 7.2-rc4 with commit 62ec41f364648be79d54d94d0d240ee326948afd

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-2026-72114
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/7d966cdee006911d3957e1a4e72cb93c39cd8c1e
	https://git.kernel.org/stable/c/1b475c0c72f44622a320a4386ce9e76f85e69bc7
	https://git.kernel.org/stable/c/deb6a697cce3f021e731df543597f37a5e54caab
	https://git.kernel.org/stable/c/59bfddea64159594feb62ef11b7d7a33c8ee3783
	https://git.kernel.org/stable/c/62ec41f364648be79d54d94d0d240ee326948afd