CVE-2026-90390 md/bitmap: resume array on backlog_store() error path
A local attacker with high privileges can cause a denial of service by triggering an error path that leaves the MD array suspended.
- 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-2026-90390?
CVE-2026-90390 is a denial of service vulnerability in Linux, published on 17 Sep 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/bitmap: resume array on backlog_store() error path
backlog_store() suspends the array before checking whether a write-mostly device exists. If no such device exists, the error path only unlocks reconfig_mutex and leaves the array suspended, blocking subsequent I/O.
Use mddev_unlock_and_resume() to release both states.
Which versions are affected by CVE-2026-90390?
How do I fix CVE-2026-90390?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-90390 being exploited?
There is no known exploitation of CVE-2026-90390 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90390, DEBIAN-CVE-2026-90390, GHSA-xj4x-xc4w-3c2g, UBUNTU-CVE-2026-90390.