CVE-2026-90215 mtd: ubi: Release device reference on busy detach
A reference counting bug in the Linux kernel UBI driver causes a memory leak and potential denial of service when detaching a busy device.
- 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-2026-90215?
CVE-2026-90215 is a memory corruption 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:
mtd: ubi: Release device reference on busy detach
ubi_detach_mtd_dev() obtains a device reference through ubi_get_device() before checking whether the UBI device is busy. The busy return path drops ubi->ref_count but leaves the device reference held, so the device object cannot be released after a later detach.
Drop the device reference before returning -EBUSY.
Which versions are affected by CVE-2026-90215?
How do I fix CVE-2026-90215?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-90215 being exploited?
There is no known exploitation of CVE-2026-90215 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90215, DEBIAN-CVE-2026-90215, GHSA-387j-r42m-fpjv, UBUNTU-CVE-2026-90215.