# CVE-2023-54323: cxl/pmem: Fix nvdimm registration races

> A race condition in the Linux kernel CXL/PMEM driver allows local attackers to cause a system crash via module loading/unloading.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54323, DEBIAN-CVE-2023-54323, GHSA-9rp2-rcxm-vpww, ROOT-OS-UBUNTU-2204-CVE-2023-54323, UBUNTU-CVE-2023-54323

## What is CVE-2023-54323?

CVE-2023-54323 is a vulnerability in Linux, published on 30 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:

cxl/pmem: Fix nvdimm registration races

A loop of the form:

    while true; do modprobe cxl_pci; modprobe -r cxl_pci; done

...fails with the following crash signature:

    BUG: kernel NULL pointer dereference, address: 0000000000000040
    [..]
    RIP: 0010:cxl_internal_send_cmd+0x5/0xb0 [cxl_core]
    [..]
    Call Trace:
     <TASK>
     cxl_pmem_ctl+0x121/0x240 [cxl_pmem]
     nvdimm_get_config_data+0xd6/0x1a0 [libnvdimm]
     nd_label_data_init+0x135/0x7e0 [libnvdimm]
     nvdimm_probe+0xd6/0x1c0 [libnvdimm]
     nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm]
     really_probe+0xde/0x380
     __driver_probe_device+0x78/0x170
     driver_probe_device+0x1f/0x90
     __device_attach_driver+0x85/0x110
     bus_for_each_drv+0x7d/0xc0
     __device_attach+0xb4/0x1e0
     bus_probe_device+0x9f/0xc0
     device_add+0x445/0x9c0
     nd_async_device_register+0xe/0x40 [libnvdimm]
     async_run_entry_fn+0x30/0x130

...namely that the bottom half of async nvdimm device registration runs
after the CXL has already torn down the context that cxl_pmem_ctl()
needs. Unlike the ACPI NFIT case that benefits from launching multiple
nvdimm device registrations in parallel from those listed in the table,
CXL is already marked PROBE_PREFER_ASYNCHRONOUS. So provide for a
synchronous registration path to preclude this scenario.

## Which versions are affected by CVE-2023-54323?


## How do I fix CVE-2023-54323?

Apply the vendor's patch.

## Is CVE-2023-54323 being exploited?

There is no known exploitation of CVE-2023-54323 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54323 and fix it if it is affected.

What it is: CVE-2023-54323 is a vulnerability in Linux, published on 30 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-2023-54323 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-2023-54323/ (Markdown: https://insights.sbomify.com/CVE-2023-54323/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54323
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54323
- OSV: https://osv.dev/vulnerability/CVE-2023-54323

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54323/
Summaries are generated and may contain mistakes; the official description above is the record.