# CVE-2026-98279: btrfs: handle lack of space when cleaning up verity items

> A local attacker can force the filesystem read-only or prevent mounting by triggering quota limits during verity cleanup, causing denial of service.

- **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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106242, BELL-CVE-2026-98279, DEBIAN-CVE-2026-98279, GHSA-ccw7-243p-5699, UBUNTU-CVE-2026-98279

## What is CVE-2026-98279?

CVE-2026-98279 is a denial of service vulnerability in Linux, published on 6 Oct 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: handle lack of space when cleaning up verity items

When enable_verity() hits the qgroup limit, rollback_verity() needs its
own metadata reservation. When the qgroup limit or lack of space refuses
the rollback, the whole filesystem is forced read-only even though the
qgroup limit was for one subvolume only. Also orphan cleanup at the next
mount fails the same way, so the leftover items are never removed: with
-EDQUOT the subvolume stays unreachable, and with -ENOSPC on a full
filesystem the next read-write mount fails.

Start transactions with btrfs_start_transaction_fallback_global_rsv() in
btrfs_orphan_cleanup(), drop_verity_items() and rollback_verity(). Those
calls only delete items and free the space in the end, so they may use
the global reserve and skip the qgroup limit, which avoids -ENOSPC and
-EDQUOT.

## Which versions are affected by CVE-2026-98279?


## How do I fix CVE-2026-98279?

Apply the vendor's patch.

## Is CVE-2026-98279 being exploited?

There is no known exploitation of CVE-2026-98279 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98279 and fix it if it is affected.

What it is: CVE-2026-98279 is a denial of service vulnerability in Linux, published on 6 Oct 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-2026-98279 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-2026-98279/ (Markdown: https://insights.sbomify.com/CVE-2026-98279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98279
- OSV: https://osv.dev/vulnerability/CVE-2026-98279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98279/
Summaries are generated and may contain mistakes; the official description above is the record.