CVE-2026-89983

What the bug is

i2c_del_adapter() frees the adapter's debugfs directory before it unregisters the adapter device, but the new_device sysfs attribute stays writable until device_del(). A write racing with removal still reaches i2c_device_probe(), which passes the freed adap->debugfs to debugfs_create_dir() as the new client's parent: BUG: KASAN: slab-use-after-free in lookup_noperm_common+0x407/0x430 Read of size 4 at addr ffff88803ef87810 by task syz.0.61/6090 lookup_noperm_common+0x407/0x430 simple_start_creating+0x9c/0x110 debugfs_start_creating+0xdb/0x1a0 debugfs_create_dir+0x24/0x350 i2c_device_probe+0x814/0xbf0 It's technically possible to create a client after i2c_deregister_clients has run. That client will never be unregistered and make wait_for_completion hang. Close the window by removing the new_device attribute at the start of i2c_del_adapter(). device_remove_file() will drain any clients left.

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/i2c/i2c-core-base.c

What this is

I2C SUBSYSTEMMAINTAINERS section matched on drivers/i2c/* · linux-i2c@vger.kernel.org · Maintained

Kernel module

i2c_core

Check it on the machine

grep -w CONFIG_I2C /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 i2c_core

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.

• bookwormYnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixie, forky, sidBnot built on amd64/cloud-amd64, arm64/cloud-arm64
• bookworm · linux-6.12Ynot built on amd64/cloud-amd64, arm64/cloud-arm64

Y

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

B

built in on some, a module on others, absent on the rest

Build switch

CONFIG_I2C

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

2026-09-16 (33 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/i2c

Upstream fixes

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

Introduced	Fixed in	Commit
5.15.168	5.15.221	dc33a9762538
6.1.113	6.1.188	1f1bcd4eca6c
6.6.55	6.6.157	f9094ace03e0
6.8	6.12.110	643fb872aa04
6.8	6.18.51	112b3d48084c
6.8	7.2.5	552836be2d95
6.8	7.3	b15b548d52b4

Debian advisories