CVE-2026-98081 btrfs: zoned: finish active block group cleanup if call_zone_finish() fails
A logic error in the Linux kernel's btrfs zoned storage handling can cause a denial of service by spinning indefinitely when zone finishing fails.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98081?
CVE-2026-98081 is a denial of service vulnerability in Linux, 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: zoned: finish active block group cleanup if call_zone_finish() fails
do_zone_finish() clears BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE before finishing the zones. If call_zone_finish() then fails it returned early, leaving the now inactive block group on fs_info->zone_active_bgs, leaking its reference, the BTRFS_FS_NEED_ZONE_FINISH waiters are never woken, and as its alloc_offset equals the zone capacity btrfs_zone_finish_one_bg() keeps selecting it, spinning btrfs_zoned_activate_one_bg().
Fall through to the cleanup on failure too and return the error, but keep the block group read-only as its zones are left inconsistent.
Which versions are affected by CVE-2026-98081?
How do I fix CVE-2026-98081?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98081 being exploited?
There is no known exploitation of CVE-2026-98081 in the wild and no public exploit code.
Sources
Also known as AZL-104561, BELL-CVE-2026-98081, DEBIAN-CVE-2026-98081, GHSA-vxgx-5rhh-g7hj, UBUNTU-CVE-2026-98081.