# CVE-2021-47113: btrfs: abort in rename_exchange if we fail to insert the second ref

> A use-after-free in the Linux kernel btrfs filesystem can cause corruption and denial of service during failed rename operations.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 15 Mar 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47113, GHSA-g4rp-89x9-87mq, UBUNTU-CVE-2021-47113

## What is CVE-2021-47113?

CVE-2021-47113 is a high-severity use after free vulnerability in Linux kernel, published on 15 Mar 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: abort in rename_exchange if we fail to insert the second ref

Error injection stress uncovered a problem where we'd leave a dangling
inode ref if we failed during a rename_exchange.  This happens because
we insert the inode ref for one side of the rename, and then for the
other side.  If this second inode ref insert fails we'll leave the first
one dangling and leave a corrupt file system behind.  Fix this by
aborting if we did the insert for the first inode ref.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2021-47113?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47113?

Apply the vendor's patch.

## Is CVE-2021-47113 being exploited?

There is no known exploitation of CVE-2021-47113 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-2021-47113 and fix it if it is affected.

What it is: CVE-2021-47113 is a high-severity use after free vulnerability in Linux kernel, published on 15 Mar 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-2021-47113 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-2021-47113/ (Markdown: https://insights.sbomify.com/CVE-2021-47113/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47113
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47113
- OSV: https://osv.dev/vulnerability/CVE-2021-47113

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47113/
Summaries are generated and may contain mistakes; the official description above is the record.