# CVE-2022-50766: btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer

> A local attacker can read uninitialized kernel memory via a race condition in the Btrfs filesystem, potentially exposing sensitive data.

- **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:** 24 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-50766, GHSA-65xq-q38h-gcrc, ROOT-OS-DEBIAN-11-CVE-2022-50766, UBUNTU-CVE-2022-50766

## What is CVE-2022-50766?

CVE-2022-50766 is a vulnerability in Linux, published on 24 Dec 2025. 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: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer

syzbot is reporting uninit-value in btrfs_clean_tree_block() [1], for
commit bc877d285ca3dba2 ("btrfs: Deduplicate extent_buffer init code")
missed that btrfs_set_header_generation() in btrfs_init_new_buffer() must
not be moved to after clean_tree_block() because clean_tree_block() is
calling btrfs_header_generation() since commit 55c69072d6bd5be1 ("Btrfs:
Fix extent_buffer usage when nodesize != leafsize").

Since memzero_extent_buffer() will reset "struct btrfs_header" part, we
can't move btrfs_set_header_generation() to before memzero_extent_buffer().
Just re-add btrfs_set_header_generation() before btrfs_clean_tree_block().

## Which versions are affected by CVE-2022-50766?


## How do I fix CVE-2022-50766?

Apply the vendor's patch.

## Is CVE-2022-50766 being exploited?

There is no known exploitation of CVE-2022-50766 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-50766 and fix it if it is affected.

What it is: CVE-2022-50766 is a vulnerability in Linux, published on 24 Dec 2025. 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-2022-50766 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-2022-50766/ (Markdown: https://insights.sbomify.com/CVE-2022-50766/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-50766
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50766
- OSV: https://osv.dev/vulnerability/CVE-2022-50766

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-50766/
Summaries are generated and may contain mistakes; the official description above is the record.