CVE-2023-53832 md/raid10: fix null-ptr-deref in raid10_sync_request
A null pointer dereference in the Linux kernel RAID10 driver allows local attackers to cause a system crash via specific I/O error and replacement scenarios.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53832?
CVE-2023-53832 is a vulnerability in Linux, published on 9 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/raid10: fix null-ptr-deref in raid10_sync_request
init_resync() inits mempool and sets conf->have_replacemnt at the beginning of sync, close_sync() frees the mempool when sync is completed.
After [1] recovery might be skipped and init_resync() is called but close_sync() is not. null-ptr-deref occurs with r10bio->dev[i].repl_bio.
The following is one way to reproduce the issue.
1) create a array, wait for resync to complete, mddev->recovery_cp is set to MaxSector. 2) recovery is woken and it is skipped. conf->have_replacement is set to 0 in init_resync(). close_sync() not called. 3) some io errors and rdev A is set to WantReplacement. 4) a new device is added and set to A's replacement. 5) recovery is woken, A have replacement, but conf->have_replacemnt is 0. r10bio->dev[i].repl_bio will not be alloced and null-ptr-deref occurs.
Fix it by not calling init_resync() if recovery skipped.
[1] commit 7e83ccbecd60 ("md/raid10: Allow skipping recovery when clean arrays are assembled")
Which versions are affected by CVE-2023-53832?
How do I fix CVE-2023-53832?
Apply the vendor's patch.
Is CVE-2023-53832 being exploited?
There is no known exploitation of CVE-2023-53832 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53832, DEBIAN-CVE-2023-53832, GHSA-f28c-m9h4-3wr6, UBUNTU-CVE-2023-53832.