# CVE-2024-50142: xfrm: validate new SA's prefixlen using SA family when sel.family is unset

> A missing validation in the Linux kernel xfrm subsystem allows attackers to cause a denial of service by creating Security Associations with invalid prefix lengths.

- **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:** 7 Nov 2024
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-53474, AZL-53745, BELL-CVE-2024-50142, DEBIAN-CVE-2024-50142, GHSA-35cx-v8jm-4qrv, UBUNTU-CVE-2024-50142

## What is CVE-2024-50142?

CVE-2024-50142 is a medium-severity denial of service vulnerability in Linux kernel, published on 7 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:

xfrm: validate new SA's prefixlen using SA family when sel.family is unset

This expands the validation introduced in commit 07bf7908950a ("xfrm:
Validate address prefix lengths in the xfrm selector.")

syzbot created an SA with
    usersa.sel.family = AF_UNSPEC
    usersa.sel.prefixlen_s = 128
    usersa.family = AF_INET

Because of the AF_UNSPEC selector, verify_newsa_info doesn't put
limits on prefixlen_{s,d}. But then copy_from_user_state sets
x->sel.family to usersa.family (AF_INET). Do the same conversion in
verify_newsa_info before validating prefixlen_{s,d}, since that's how
prefixlen is going to be used later on.

## Which versions are affected by CVE-2024-50142?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-50142?

Apply the vendor's patch.

## Is CVE-2024-50142 being exploited?

There is no known exploitation of CVE-2024-50142 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-2024-50142 and fix it if it is affected.

What it is: CVE-2024-50142 is a medium-severity denial of service vulnerability in Linux kernel, published on 7 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-2024-50142 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-2024-50142/ (Markdown: https://insights.sbomify.com/CVE-2024-50142/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-50142
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-50142
- OSV: https://osv.dev/vulnerability/CVE-2024-50142

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-50142/
Summaries are generated and may contain mistakes; the official description above is the record.