CVE-2026-72337

What the bug is

lowpan_enable_set() allocates a temporary work item and schedules do_enable_set() on system_wq, then returns to debugfs. The debugfs active operation has ended at that point, but the worker still executes module text and manipulates enable_6lowpan and listen_chan. bt_6lowpan_exit() removes the debugfs files and immediately closes and puts listen_chan. It has no pointer to the queued work item, so it cannot cancel or flush it before tearing down the state that the worker uses. The buggy scenario involves two paths, with each column showing the order within that path: debugfs enable write module exit 1. lowpan_enable_set() allocates 1. bt_6lowpan_exit() removes set_enable work the debugfs file 2. schedule_work() queues 2. bt_6lowpan_exit() closes do_enable_set() and puts listen_chan 3. the write operation returns 3. module teardown can continue 4. do_enable_set() later runs against stale state Run the enable state transition synchronously in lowpan_enable_set() instead. The simple debugfs setter can sleep, and this file already handles the 6LoWPAN control write synchronously under the same set_lock. Once the setter returns, debugfs removal covers the whole operation and exit can no longer race with an untracked work item. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in do_enable_set+0x113/0x2e0 Workqueue: events do_enable_set [bluetooth_6lowpan] The buggy address belongs to the object at ffff888109cb8000

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.

net/bluetooth/6lowpan.c

What this is

BLUETOOTH SUBSYSTEMMAINTAINERS section matched on net/bluetooth/ · linux-bluetooth@vger.kernel.org · Supported

Kernel module

bluetooth_6lowpan

Check it on the machine

grep -wE 'CONFIG_BT|CONFIG_BT_6LOWPAN' /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 bluetooth_6lowpan

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_6LOWPAN

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

2026-08-15 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.1% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/bluetooth

Upstream fixes

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

Introduced	Fixed in	Commit
3.19	6.18.57	31cc289d5b17
3.19	7.1.5	feb3fc2c38ed
3.19	7.2	352a59dc1f4a