CVE-2026-90389 md: scope memalloc_noio to allocation critical sections
A race condition in the Linux kernel md driver allows local attackers to corrupt memory allocation flags, potentially leading to privilege escalation or system instability.
- 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-2026-90389?
CVE-2026-90389 is a 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: scope memalloc_noio to allocation critical sections
Storing a memalloc_noio_save() token in mddev->noio_flags lets one task save the token and another task restore it. With concurrent suspend sysfs writes, task A can enter PF_MEMALLOC_NOIO, return to userspace still in that scope, and later task B can restore A's saved token.
Avoid tying the token lifetime to mddev. Keep mddev_suspend() and mddev_resume() only responsible for array suspension, and enter PF_MEMALLOC_NOIO only in the MD paths that allocate memory after the array has been suspended. Restore the token before resuming the array.
A reproducer repeatedly writes suspend_lo and suspend_hi from concurrent workers and checks each worker's /proc/self/stat flags before and after the sysfs write.
Which versions are affected by CVE-2026-90389?
How do I fix CVE-2026-90389?
Apply the vendor's patch.
Is CVE-2026-90389 being exploited?
There is no known exploitation of CVE-2026-90389 in the wild and no public exploit code.
Sources
Also known as AZL-102111, BELL-CVE-2026-90389, DEBIAN-CVE-2026-90389, GHSA-p657-p2pf-57vf, UBUNTU-CVE-2026-90389.