CVE-2026-98090 btrfs: restore active device pointers after failed sprout

Medium 5.5 Published Updated

A use-after-free in the Linux kernel btrfs filesystem allows a local attacker with high privileges to cause a system crash by triggering a failed device sprout operation.

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-2026-98090?

CVE-2026-98090 is a medium-severity use after free vulnerability in Linux kernel, published on 25 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:

btrfs: restore active device pointers after failed sprout

btrfs_init_new_device() switches latest_dev and possibly s_bdev from the seed device to the new sprout device before creating the first writable chunks.

If chunk creation or the subsequent sprout setup fails, the error path releases the new device without switching those pointers back. btrfs_show_devname() can then dereference the freed latest_dev and crash.

Restore the active device pointers to the latest seed device before removing and releasing the failed sprout device.

Weakness: CWE-416

Which versions are affected by CVE-2026-98090?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-98090?

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-2026-98090 being exploited?

There is no known exploitation of CVE-2026-98090 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-104367, BELL-CVE-2026-98090, DEBIAN-CVE-2026-98090, GHSA-j9r6-v9mw-fjh8, UBUNTU-CVE-2026-98090.

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