# CVE-2022-48733: btrfs: fix use-after-free after failure to create a snapshot

> A use-after-free in the Linux kernel btrfs filesystem allows local attackers to potentially execute code or escalate privileges via snapshot creation failures.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Jun 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-48733, GHSA-grhv-62hf-9jg3, UBUNTU-CVE-2022-48733

## What is CVE-2022-48733?

CVE-2022-48733 is a high-severity use after free vulnerability in Linux kernel, published on 20 Jun 2024. 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: fix use-after-free after failure to create a snapshot

At ioctl.c:create_snapshot(), we allocate a pending snapshot structure and
then attach it to the transaction's list of pending snapshots. After that
we call btrfs_commit_transaction(), and if that returns an error we jump
to 'fail' label, where we kfree() the pending snapshot structure. This can
result in a later use-after-free of the pending snapshot:

1) We allocated the pending snapshot and added it to the transaction's
   list of pending snapshots;

2) We call btrfs_commit_transaction(), and it fails either at the first
   call to btrfs_run_delayed_refs() or btrfs_start_dirty_block_groups().
   In both cases, we don't abort the transaction and we release our
   transaction handle. We jump to the 'fail' label and free the pending
   snapshot structure. We return with the pending snapshot still in the
   transaction's list;

3) Another task commits the transaction. This time there's no error at
   all, and then during the transaction commit it accesses a pointer
   to the pending snapshot structure that the snapshot creation task
   has already freed, resulting in a user-after-free.

This issue could actually be detected by smatch, which produced the
following warning:

  fs/btrfs/ioctl.c:843 create_snapshot() warn: '&pending_snapshot->list' not removed from list

So fix this by not having the snapshot creation ioctl directly add the
pending snapshot to the transaction's list. Instead add the pending
snapshot to the transaction handle, and then at btrfs_commit_transaction()
we add the snapshot to the list only when we can guarantee that any error
returned after that point will result in a transaction abort, in which
case the ioctl code can safely free the pending snapshot and no one can
access it anymore.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-48733?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48733?

Apply the vendor's patch.

## Is CVE-2022-48733 being exploited?

There is no known exploitation of CVE-2022-48733 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-48733 and fix it if it is affected.

What it is: CVE-2022-48733 is a high-severity use after free vulnerability in Linux kernel, published on 20 Jun 2024. 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-2022-48733 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2022-48733/ (Markdown: https://insights.sbomify.com/CVE-2022-48733/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48733
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48733
- OSV: https://osv.dev/vulnerability/CVE-2022-48733

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48733/
Summaries are generated and may contain mistakes; the official description above is the record.