From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-98294: Bluetooth: hci_qca: Do not write to the serial port after it is closed
Date: Tue, 6 Oct 2026 10:46:35 +0200 [thread overview]
Message-ID: <2026100607-CVE-2026-98294-95ae@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_qca: Do not write to the serial port after it is closed
hci_uart_close() closes the serdev port if HCI_QUIRK_NON_PERSISTENT_SETUP
is set (for example, for the WCN399x family). A failed hci_dev_open_sync()
following a successful qca_setup() calls hdev->close() but not
hdev->shutdown(), so the port is closed while power->vregs_on is left true.
qca_serdev_remove() then passes its power->vregs_on test and calls
qca_power_off(), which writes to the closed port unconditionally.
Seen on a WCN3988 by unbinding the driver after a controller failure. The
trace below is from a 7.0.0 based kernel, where qca_power_off() was still
named qca_power_shutdown():
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000038
Call trace:
tty_set_termios+0x50/0x238 (P)
ttyport_set_baudrate+0x84/0xc0
serdev_device_set_baudrate+0x24/0x40
qca_power_shutdown+0x158/0x1fc [hci_uart]
qca_serdev_remove+0x54/0x68 [hci_uart]
serdev_drv_remove+0x1c/0x2c
device_remove+0x4c/0x80
device_release_driver_internal+0x1cc/0x224
device_driver_detach+0x18/0x24
unbind_store+0xb4/0xc0
Check HCI_UART_PROTO_READY, which hci_uart_close() clears in the same place
it closes the port, before writing to it. The regulator disable is left
unconditional so the controller is still powered down.
The dangling serport->tty that turns this into a use-after-free is
addressed in a separate patch.
The Linux kernel CVE team has assigned CVE-2026-98294 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.19 with commit fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and fixed in 6.18.54 with commit a5414b0a9464b863733c8bd97493cb443a210ec4
Issue introduced in 4.19 with commit fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and fixed in 7.2.8 with commit 15754e4ec47ac5d117c9609c34a49ed6980ac4a1
Issue introduced in 4.19 with commit fa9ad876b8e0ebd2b4367ef1580f89be64ebd5d3 and fixed in 7.3-rc4 with commit 4e93c65f87825e1e012bce56615320aeb123815d
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-2026-98294
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_qca.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/a5414b0a9464b863733c8bd97493cb443a210ec4
https://git.kernel.org/stable/c/15754e4ec47ac5d117c9609c34a49ed6980ac4a1
https://git.kernel.org/stable/c/4e93c65f87825e1e012bce56615320aeb123815d
reply other threads:[~2026-10-06 10:26 UTC|newest]
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