# CVE-2023-53496: x86/platform/uv: Use alternate source for socket to node data

> A null dereference in the Linux kernel UV platform code causes system crashes when CPU counts are misconfigured, leading to denial of service.

- **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:** 1 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53496, DEBIAN-CVE-2023-53496, GHSA-q4x7-5j3j-pvx9, UBUNTU-CVE-2023-53496

## What is CVE-2023-53496?

CVE-2023-53496 is a medium-severity vulnerability in Linux kernel, published on 1 Oct 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:

x86/platform/uv: Use alternate source for socket to node data

The UV code attempts to build a set of tables to allow it to do
bidirectional socket<=>node lookups.

But when nr_cpus is set to a smaller number than actually present, the
cpu_to_node() mapping information for unused CPUs is not available to
build_socket_tables(). This results in skipping some nodes or sockets
when creating the tables and leaving some -1's for later code to trip.
over, causing oopses.

The problem is that the socket<=>node lookups are created by doing a
loop over all CPUs, then looking up the CPU's APICID and socket. But
if a CPU is not present, there is no way to start this lookup.

Instead of looping over all CPUs, take CPUs out of the equation
entirely. Loop over all APICIDs which are mapped to a valid NUMA node.
Then just extract the socket-id from the APICID.

This avoid tripping over disabled CPUs.

## Which versions are affected by CVE-2023-53496?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53496?

Apply the vendor's patch.

## Is CVE-2023-53496 being exploited?

There is no known exploitation of CVE-2023-53496 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-2023-53496 and fix it if it is affected.

What it is: CVE-2023-53496 is a medium-severity vulnerability in Linux kernel, published on 1 Oct 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-2023-53496 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-2023-53496/ (Markdown: https://insights.sbomify.com/CVE-2023-53496/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53496
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53496
- OSV: https://osv.dev/vulnerability/CVE-2023-53496

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53496/
Summaries are generated and may contain mistakes; the official description above is the record.