# CVE-2023-54062: ext4: fix invalid free tracking in ext4_xattr_move_to_block()

> A use-after-free vulnerability in the Linux kernel ext4 filesystem allows attackers to cause denial of service or potentially execute code via crafted extended attributes.

- **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:** 24 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2023-54062, DEBIAN-CVE-2023-54062, GHSA-3m76-cj86-mwp4, UBUNTU-CVE-2023-54062

## What is CVE-2023-54062?

CVE-2023-54062 is a high-severity use after free 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:

ext4: fix invalid free tracking in ext4_xattr_move_to_block()

In ext4_xattr_move_to_block(), the value of the extended attribute
which we need to move to an external block may be allocated by
kvmalloc() if the value is stored in an external inode.  So at the end
of the function the code tried to check if this was the case by
testing entry->e_value_inum.

However, at this point, the pointer to the xattr entry is no longer
valid, because it was removed from the original location where it had
been stored.  So we could end up calling kvfree() on a pointer which
was not allocated by kvmalloc(); or we could also potentially leak
memory by not freeing the buffer when it should be freed.  Fix this by
storing whether it should be freed in a separate variable.

## Which versions are affected by CVE-2023-54062?


## How do I fix CVE-2023-54062?

Apply the vendor's patch.

## Is CVE-2023-54062 being exploited?

There is no known exploitation of CVE-2023-54062 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54062 and fix it if it is affected.

What it is: CVE-2023-54062 is a high-severity use after free 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-2023-54062 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-2023-54062/ (Markdown: https://insights.sbomify.com/CVE-2023-54062/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54062
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54062
- OSV: https://osv.dev/vulnerability/CVE-2023-54062

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54062/
Summaries are generated and may contain mistakes; the official description above is the record.