# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104561, BELL-CVE-2026-98081, DEBIAN-CVE-2026-98081, GHSA-vxgx-5rhh-g7hj, UBUNTU-CVE-2026-98081

## 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.

## Is CVE-2026-98081 being exploited?

There is no known exploitation of CVE-2026-98081 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98081 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-98081 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98081/ (Markdown: https://insights.sbomify.com/CVE-2026-98081/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98081
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98081
- OSV: https://osv.dev/vulnerability/CVE-2026-98081

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98081/
Summaries are generated and may contain mistakes; the official description above is the record.