# CVE-2023-52497: erofs: fix lz4 inplace decompression

> A memory corruption flaw in the Linux kernel's EROFS filesystem allows data corruption or denial of service during LZ4 decompression on specific hardware.

- **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:** 29 Feb 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-52497, DEBIAN-CVE-2023-52497, GHSA-7hmq-6483-qr84, UBUNTU-CVE-2023-52497

## What is CVE-2023-52497?

CVE-2023-52497 is a high-severity memory corruption vulnerability in Linux kernel, published on 29 Feb 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:

erofs: fix lz4 inplace decompression

Currently EROFS can map another compressed buffer for inplace
decompression, that was used to handle the cases that some pages of
compressed data are actually not in-place I/O.

However, like most simple LZ77 algorithms, LZ4 expects the compressed
data is arranged at the end of the decompressed buffer and it
explicitly uses memmove() to handle overlapping:
  __________________________________________________________
 |_ direction of decompression --> ____ |_ compressed data _|

Although EROFS arranges compressed data like this, it typically maps two
individual virtual buffers so the relative order is uncertain.
Previously, it was hardly observed since LZ4 only uses memmove() for
short overlapped literals and x86/arm64 memmove implementations seem to
completely cover it up and they don't have this issue.  Juhyung reported
that EROFS data corruption can be found on a new Intel x86 processor.
After some analysis, it seems that recent x86 processors with the new
FSRM feature expose this issue with "rep movsb".

Let's strictly use the decompressed buffer for lz4 inplace
decompression for now.  Later, as an useful improvement, we could try
to tie up these two buffers together in the correct order.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-52497?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52497?

Apply the vendor's patch.

## Is CVE-2023-52497 being exploited?

There is no known exploitation of CVE-2023-52497 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-2023-52497 and fix it if it is affected.

What it is: CVE-2023-52497 is a high-severity memory corruption vulnerability in Linux kernel, published on 29 Feb 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-2023-52497 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-2023-52497/ (Markdown: https://insights.sbomify.com/CVE-2023-52497/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52497
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52497
- OSV: https://osv.dev/vulnerability/CVE-2023-52497

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52497/
Summaries are generated and may contain mistakes; the official description above is the record.