# CVE-2026-74319: btrfs: zoned: fix deadlock waiting for ticket during data relocation

> A deadlock in the Linux kernel's Btrfs zoned filesystem code allows local attackers to cause a denial of service during data relocation.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-74319, GHSA-w48h-wv4w-hrq6, UBUNTU-CVE-2026-74319

## What is CVE-2026-74319?

CVE-2026-74319 is a denial of service vulnerability in Linux, published on 15 Aug 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: fix deadlock waiting for ticket during data relocation

When performing data relocation on a zoned filesystem, BTRFS can deadlock
in handle_reserve_tickets(). The relocation process is waiting on a space
reservation ticket that can never be fulfilled, because the relocation
itself is the operation responsible for freeing up that space.

Fix this by introducing a new flush state,
BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, specifically for data chunk
allocation during zoned relocation. Like
BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE, this state uses
priority_reclaim_data_space() instead of the normal flushing path, which
avoids re-entering the relocation code and breaking the deadlock cycle.

In btrfs_alloc_data_chunk_ondemand(), select this new flush state when the
inode belongs to a data relocation root on a zoned filesystem.

## Which versions are affected by CVE-2026-74319?


## How do I fix CVE-2026-74319?

Apply the vendor's patch.

## Is CVE-2026-74319 being exploited?

There is no known exploitation of CVE-2026-74319 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74319 and fix it if it is affected.

What it is: CVE-2026-74319 is a denial of service vulnerability in Linux, published on 15 Aug 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-2026-74319 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-2026-74319/ (Markdown: https://insights.sbomify.com/CVE-2026-74319/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74319
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74319
- OSV: https://osv.dev/vulnerability/CVE-2026-74319

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74319/
Summaries are generated and may contain mistakes; the official description above is the record.