CVE-2026-68085: Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work is canceled

CVE-2026-68085: Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work is canceled

[Greg Kroah-Hartman]

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

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

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

Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work is canceled

HCI_UART_SENDING bit in tx_state means write_work is pending and blocks
queueing it again.  Currently this bit is not cleared when canceling the
work in hci_uart_close(), which blocks future writes when device is
reopened later if write_work was pending.

Fix by clearing HCI_UART_SENDING when canceling the work.

Also make clearing of tx_skb safe by using disable_work_sync +
enable_work instead of just cancel_work_sync.  hci_uart_flush() purges
the proto tx queue so we can cancel the pending write_work there,
instead of doing it just in hci_uart_close().  Re-enable and possibly
requeue the work after queue flush.

The Linux kernel CVE team has assigned CVE-2026-68085 to this issue.


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

	Issue introduced in 6.12.92 with commit 81c7a3c22a0f2808cf4ae0b4908f59763b23606d and fixed in 6.12.96 with commit d52446b3e735cfdbdc2a58342163803bc2e64249
	Issue introduced in 6.18.34 with commit 192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894 and fixed in 6.18.39 with commit b9dd39cf1667e378b25a082ca796d495d578c5d3
	Issue introduced in 7.1 with commit c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b and fixed in 7.1.4 with commit 714d861d35d937f23375a4517569b13917bbbe51
	Issue introduced in 7.1 with commit c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b and fixed in 7.2-rc3 with commit 1b0d946d6f08bd39211385bc703a440911b41e46
	Issue introduced in 5.10.258 with commit 78aad93e938f013d9272fe0ee168f27883afa95c
	Issue introduced in 5.15.209 with commit e2d19969c8d9198ecc3090bcd5312ecd503a3339
	Issue introduced in 6.1.175 with commit c85cff648a2bc92322912db5f1727ad05afae7b6
	Issue introduced in 6.6.142 with commit 9d20d48be2c4a071fb015eb09bda2cecd25daf34
	Issue introduced in 7.0.11 with commit 7338031946bd06f6dff149e67b60c4cd083bfea8

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-2026-68085
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/hci_ldisc.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/d52446b3e735cfdbdc2a58342163803bc2e64249
	https://git.kernel.org/stable/c/b9dd39cf1667e378b25a082ca796d495d578c5d3
	https://git.kernel.org/stable/c/714d861d35d937f23375a4517569b13917bbbe51
	https://git.kernel.org/stable/c/1b0d946d6f08bd39211385bc703a440911b41e46