CVE-2026-98294

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/bluetooth/hci_qca.c

What this is

QUALCOMM BLUETOOTH DRIVERMAINTAINERS section matched on drivers/bluetooth/hci_qca.c · linux-arm-msm@vger.kernel.org · Maintained

Kernel module

hci_uart

Check it on the machine

grep -wE 'CONFIG_BT|CONFIG_BT_HCIUART|CONFIG_BT_HCIUART_QCA' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w hci_uart

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x

M

a module where it is built at all; some flavours do not build it

Build switches

CONFIG_BT, CONFIG_BT_HCIUART, CONFIG_BT_HCIUART_QCA

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-10-06 (13 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.17%, higher than 6.3% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/bluetooth

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
4.19	6.18.54	a5414b0a9464
4.19	7.2.8	15754e4ec47a
4.19	7.3	4e93c65f8782