CVE-2025-68368 md: init bioset in mddev_init
A local attacker with high privileges can trigger a kernel NULL pointer dereference in the md driver, causing a system crash.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68368?
CVE-2025-68368 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
md: init bioset in mddev_init
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.
Which versions are affected by CVE-2025-68368?
How do I fix CVE-2025-68368?
Apply the vendor's patch.
Is CVE-2025-68368 being exploited?
There is no known exploitation of CVE-2025-68368 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68368, DEBIAN-CVE-2025-68368, GHSA-8jvw-6j3w-p767, ROOT-OS-DEBIAN-13-CVE-2025-68368, UBUNTU-CVE-2025-68368.