# CVE-2024-44948: x86/mtrr: Check if fixed MTRRs exist before saving them

> A missing capability check in the Linux kernel x86 MTRR code causes a warning on CPUs without fixed MTRR support, potentially leading to system instability or 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:** 4 Sep 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-44948, DEBIAN-CVE-2024-44948, GHSA-7p6j-4w59-cjvv, UBUNTU-CVE-2024-44948

## What is CVE-2024-44948?

CVE-2024-44948 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 Sep 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:

x86/mtrr: Check if fixed MTRRs exist before saving them

MTRRs have an obsolete fixed variant for fine grained caching control
of the 640K-1MB region that uses separate MSRs. This fixed variant has
a separate capability bit in the MTRR capability MSR.

So far all x86 CPUs which support MTRR have this separate bit set, so it
went unnoticed that mtrr_save_state() does not check the capability bit
before accessing the fixed MTRR MSRs.

Though on a CPU that does not support the fixed MTRR capability this
results in a #GP.  The #GP itself is harmless because the RDMSR fault is
handled gracefully, but results in a WARN_ON().

Add the missing capability check to prevent this.

## Which versions are affected by CVE-2024-44948?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-44948?

Apply the vendor's patch.

## Is CVE-2024-44948 being exploited?

There is no known exploitation of CVE-2024-44948 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-2024-44948 and fix it if it is affected.

What it is: CVE-2024-44948 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 Sep 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-2024-44948 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-2024-44948/ (Markdown: https://insights.sbomify.com/CVE-2024-44948/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-44948
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-44948
- OSV: https://osv.dev/vulnerability/CVE-2024-44948

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-44948/
Summaries are generated and may contain mistakes; the official description above is the record.