# CVE-2023-52449: mtd: Fix gluebi NULL pointer dereference caused by ftl notifier

> A NULL pointer dereference in the Linux kernel MTD subsystem can cause a denial of service when specific modules are loaded.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 22 Feb 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-52449, DEBIAN-CVE-2023-52449, GHSA-268r-8rwm-mqq9, UBUNTU-CVE-2023-52449

## What is CVE-2023-52449?

CVE-2023-52449 is a medium-severity vulnerability in Linux kernel, published on 22 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:

mtd: Fix gluebi NULL pointer dereference caused by ftl notifier

If both ftl.ko and gluebi.ko are loaded, the notifier of ftl
triggers NULL pointer dereference when trying to access
‘gluebi->desc’ in gluebi_read().

ubi_gluebi_init
  ubi_register_volume_notifier
    ubi_enumerate_volumes
      ubi_notify_all
        gluebi_notify    nb->notifier_call()
          gluebi_create
            mtd_device_register
              mtd_device_parse_register
                add_mtd_device
                  blktrans_notify_add   not->add()
                    ftl_add_mtd         tr->add_mtd()
                      scan_header
                        mtd_read
                          mtd_read_oob
                            mtd_read_oob_std
                              gluebi_read   mtd->read()
                                gluebi->desc - NULL

Detailed reproduction information available at the Link [1],

In the normal case, obtain gluebi->desc in the gluebi_get_device(),
and access gluebi->desc in the gluebi_read(). However,
gluebi_get_device() is not executed in advance in the
ftl_add_mtd() process, which leads to NULL pointer dereference.

The solution for the gluebi module is to run jffs2 on the UBI
volume without considering working with ftl or mtdblock [2].
Therefore, this problem can be avoided by preventing gluebi from
creating the mtdblock device after creating mtd partition of the
type MTD_UBIVOLUME.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-52449?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52449?

Apply the vendor's patch.

## Is CVE-2023-52449 being exploited?

There is no known exploitation of CVE-2023-52449 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-2023-52449 and fix it if it is affected.

What it is: CVE-2023-52449 is a medium-severity vulnerability in Linux kernel, published on 22 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-2023-52449 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-2023-52449/ (Markdown: https://insights.sbomify.com/CVE-2023-52449/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52449
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52449
- OSV: https://osv.dev/vulnerability/CVE-2023-52449

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52449/
Summaries are generated and may contain mistakes; the official description above is the record.