# CVE-2024-50263: fork: only invoke khugepaged, ksm hooks if no error

> A flaw in the Linux kernel's fork operation could lead to a null pointer dereference when memory allocation fails, causing a system crash.

- **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:** 11 Nov 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-50263, DEBIAN-CVE-2024-50263, GHSA-5mmf-rjpr-m4cj, UBUNTU-CVE-2024-50263

## What is CVE-2024-50263?

CVE-2024-50263 is a high-severity vulnerability in Linux kernel, published on 11 Nov 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:

fork: only invoke khugepaged, ksm hooks if no error

There is no reason to invoke these hooks early against an mm that is in an
incomplete state.

The change in commit d24062914837 ("fork: use __mt_dup() to duplicate
maple tree in dup_mmap()") makes this more pertinent as we may be in a
state where entries in the maple tree are not yet consistent.

Their placement early in dup_mmap() only appears to have been meaningful
for early error checking, and since functionally it'd require a very small
allocation to fail (in practice 'too small to fail') that'd only occur in
the most dire circumstances, meaning the fork would fail or be OOM'd in
any case.

Since both khugepaged and KSM tracking are there to provide optimisations
to memory performance rather than critical functionality, it doesn't
really matter all that much if, under such dire memory pressure, we fail
to register an mm with these.

As a result, we follow the example of commit d2081b2bf819 ("mm:
khugepaged: make khugepaged_enter() void function") and make ksm_fork() a
void function also.

We only expose the mm to these functions once we are done with them and
only if no error occurred in the fork operation.

## Which versions are affected by CVE-2024-50263?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-50263?

Apply the vendor's patch.

## Is CVE-2024-50263 being exploited?

There is no known exploitation of CVE-2024-50263 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-2024-50263 and fix it if it is affected.

What it is: CVE-2024-50263 is a high-severity vulnerability in Linux kernel, published on 11 Nov 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-2024-50263 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-2024-50263/ (Markdown: https://insights.sbomify.com/CVE-2024-50263/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-50263
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-50263
- OSV: https://osv.dev/vulnerability/CVE-2024-50263

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-50263/
Summaries are generated and may contain mistakes; the official description above is the record.