CVE-2025-68368

What the bug is

IO operations may be needed before md_run(), such as updating metadata after writing sysfs. Without bioset, this triggers a NULL pointer dereference as below: BUG: kernel NULL pointer dereference, address: 0000000000000020 Call Trace: md_update_sb+0x658/0xe00 new_level_store+0xc5/0x120 md_attr_store+0xc9/0x1e0 sysfs_kf_write+0x6f/0xa0 kernfs_fop_write_iter+0x141/0x2a0 vfs_write+0x1fc/0x5a0 ksys_write+0x79/0x180 __x64_sys_write+0x1d/0x30 x64_sys_call+0x2818/0x2880 do_syscall_64+0xa9/0x580 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Reproducer ``` mdadm -CR /dev/md0 -l1 -n2 /dev/sd[cd] echo inactive > /sys/block/md0/md/array_state echo 10 > /sys/block/md0/md/new_level ``` mddev_init() can only be called once per mddev, no need to test if bioset has been initialized anymore.

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/md/md.c

What this is

SOFTWARE RAID (Multiple Disks) SUPPORTMAINTAINERS section matched on drivers/md/md* · linux-raid@vger.kernel.org · Supported

Kernel module

md_mod

Check it on the machine

grep -wE 'CONFIG_BLK_DEV_MD|CONFIG_MD' /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 md_mod

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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.

• bookworm, trixie, forky, sidm

m

a loadable module on every flavour - check lsmod, can be blacklisted

Build switches

CONFIG_BLK_DEV_MD, CONFIG_MD

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

2025-12-24 (10 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.17%, higher than 6.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

drivers/md

Upstream fixes

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

Introduced	Fixed in	Commit
6.12	6.18.2	9d37fe37dfa0
6.12	6.19	381a3ce1c0ff