CVE-2026-64407: Bluetooth: btnxpuart: Fix out-of-bounds firmware read in nxp_recv_fw_req_v3()

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

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

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

Bluetooth: btnxpuart: Fix out-of-bounds firmware read in nxp_recv_fw_req_v3()

During the v3 firmware download the controller sends a v3_data_req with a
32 bit offset and a 16 bit len. nxp_recv_fw_req_v3() checks only the lower
bound of the offset and then sends firmware from that offset.

  nxpdev->fw_dnld_v3_offset = offset - nxpdev->fw_v3_offset_correction;
  serdev_device_write_buf(nxpdev->serdev, nxpdev->fw->data +
                          nxpdev->fw_dnld_v3_offset, len);

Nothing checks that fw_dnld_v3_offset + len stays within nxpdev->fw->size,
so a controller that asks for an offset or length past the firmware image
makes the driver read past the end of nxpdev->fw->data and send that
memory back over UART.

nxp_recv_fw_req_v1() already bounds the same write. Add the equivalent
check to the v3 path, reject the request when it falls outside the firmware
image, and zero len on the error path so the fw_v3_prev_sent bookkeeping at
free_skb stays consistent.

The Linux kernel CVE team has assigned CVE-2026-64407 to this issue.


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

	Issue introduced in 6.4 with commit 689ca16e523278470c38832a3010645a78c544d8 and fixed in 6.6.145 with commit 21e60eb4d95854196e7c0e77383f35e7ac95df61
	Issue introduced in 6.4 with commit 689ca16e523278470c38832a3010645a78c544d8 and fixed in 6.12.96 with commit 441088792ffec3ca01f4efe2934060570eb11eb8
	Issue introduced in 6.4 with commit 689ca16e523278470c38832a3010645a78c544d8 and fixed in 6.18.39 with commit 2a68a773089204af1c8581dc79668b775418c5ee
	Issue introduced in 6.4 with commit 689ca16e523278470c38832a3010645a78c544d8 and fixed in 7.1.4 with commit 49bcb39e3a041ce26021f77971eaccb49a275118
	Issue introduced in 6.4 with commit 689ca16e523278470c38832a3010645a78c544d8 and fixed in 7.2-rc3 with commit badff6c3bed8923a1257a853f137d447976eec30

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-2026-64407
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/bluetooth/btnxpuart.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/21e60eb4d95854196e7c0e77383f35e7ac95df61
	https://git.kernel.org/stable/c/441088792ffec3ca01f4efe2934060570eb11eb8
	https://git.kernel.org/stable/c/2a68a773089204af1c8581dc79668b775418c5ee
	https://git.kernel.org/stable/c/49bcb39e3a041ce26021f77971eaccb49a275118
	https://git.kernel.org/stable/c/badff6c3bed8923a1257a853f137d447976eec30