CVE-2026-93075 dax/fsdev: clear pgmap ops and owner on unbind
A use-after-free vulnerability in the Linux kernel DAX fsdev driver allows local attackers to execute arbitrary code or cause a denial of service via stale pointers after device unbind.
- 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-2026-93075?
CVE-2026-93075 is an use after free 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:
dax/fsdev: clear pgmap ops and owner on unbind
fsdev_dax_probe() sets pgmap->ops = &fsdev_pagemap_ops and pgmap->owner = dev_dax, but nothing ever clears them. For a dynamic device the pgmap is devm-allocated and freed on unbind, so this is harmless. For a static device the pgmap is the shared, long-lived one owned by the dax bus (kill_dev_dax() only NULLs dev_dax->pgmap for the non-static case), and device.c's probe sets only pgmap->type, never clearing ops/owner.
So after fsdev unbinds a static device the stale fsdev_pagemap_ops survives on the shared pgmap. If the device is then rebound to device_dax (MEMORY_DEVICE_GENERIC, which installs no ->memory_failure), or the fsdev_dax module is unloaded, a subsequent memory_failure on that pgmap dispatches through the stale -- and possibly freed -- handler.
Register a devm action that clears pgmap->ops and pgmap->owner on unbind, symmetric with setting them at probe, so the pgmap carries no fsdev state once fsdev is detached.
Which versions are affected by CVE-2026-93075?
How do I fix CVE-2026-93075?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-93075 being exploited?
There is no known exploitation of CVE-2026-93075 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-93075, GHSA-m6jw-vjqw-78fh, UBUNTU-CVE-2026-93075.