CVE-2025-71135 md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt()
A null-pointer dereference in the Linux kernel's RAID5 subsystem can cause a system crash when configuring group thread counts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-71135?
CVE-2025-71135 is a medium-severity vulnerability in Linux kernel, published on 14 Jan 2026. 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/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt()
The variable mddev->private is first assigned to conf and then checked:
conf = mddev->private; if (!conf) ...
If conf is NULL, then mddev->private is also NULL. In this case, null-pointer dereferences can occur when calling raid5_quiesce():
raid5_quiesce(mddev, true); raid5_quiesce(mddev, false);
since mddev->private is assigned to conf again in raid5_quiesce(), and conf is dereferenced in several places, for example:
conf->quiesce = 0; wake_up(&conf->wait_for_quiescent);
To fix this issue, the function should unlock mddev and return before invoking raid5_quiesce() when conf is NULL, following the existing pattern in raid5_change_consistency_policy().
Weakness: CWE-476
Which versions are affected by CVE-2025-71135?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-71135?
Apply the vendor's patch.
Is CVE-2025-71135 being exploited?
There is no known exploitation of CVE-2025-71135 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-71135, DEBIAN-CVE-2025-71135, GHSA-w8wp-w464-6xr8, ROOT-OS-UBUNTU-2404-CVE-2025-71135, UBUNTU-CVE-2025-71135.