CVE-2026-98091 btrfs: detach failed sprout device from transaction update list

Medium 5.5 Published Updated

A use-after-free in the Linux kernel btrfs filesystem allows local attackers to cause a denial of service or potentially execute code by triggering a failed sprout device creation.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2026-98091?

CVE-2026-98091 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: detach failed sprout device from transaction update list

When creating the first metadata chunk for a sprout filesystem, create_chunk() adds the new device to the transaction dev_update_list through device->post_commit_list.

If the subsequent system chunk creation fails, btrfs_init_new_device() aborts the transaction and releases the device while post_commit_list is still linked. This triggers a warning in btrfs_free_device() and leaves the transaction list referencing freed memory.

Detach the device while holding chunk_mutex before releasing it.

Weakness: CWE-416

Which versions are affected by CVE-2026-98091?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-98091?

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-2026-98091 being exploited?

There is no known exploitation of CVE-2026-98091 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-104841, BELL-CVE-2026-98091, DEBIAN-CVE-2026-98091, GHSA-frx7-8j8j-mc25, UBUNTU-CVE-2026-98091.

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