# CVE-2024-43819: kvm: s390: Reject memory region operations for ucontrol VMs

> A null pointer dereference in the Linux kernel KVM s390 subsystem allows local attackers to cause a denial of service by triggering specific memory region operations on ucontrol VMs.

- **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:** 17 Aug 2024
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-48480, AZL-48517, BELL-CVE-2024-43819, DEBIAN-CVE-2024-43819, GHSA-p6j3-p28j-4x3h, ROOT-OS-DEBIAN-11-CVE-2024-43819, ROOT-OS-DEBIAN-12-CVE-2024-43819, UBUNTU-CVE-2024-43819

## What is CVE-2024-43819?

CVE-2024-43819 is a medium-severity vulnerability in Linux kernel, published on 17 Aug 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:

kvm: s390: Reject memory region operations for ucontrol VMs

This change rejects the KVM_SET_USER_MEMORY_REGION and
KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM.
This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and
would thus result in a null pointer dereference further in.
Memory management needs to be performed in userspace and using the
ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION
and KVM_SET_USER_MEMORY_REGION2.

[frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-43819?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-43819?

Apply the vendor's patch.

## Is CVE-2024-43819 being exploited?

There is no known exploitation of CVE-2024-43819 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-2024-43819 and fix it if it is affected.

What it is: CVE-2024-43819 is a medium-severity vulnerability in Linux kernel, published on 17 Aug 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-2024-43819 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-2024-43819/ (Markdown: https://insights.sbomify.com/CVE-2024-43819/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-43819
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-43819
- OSV: https://osv.dev/vulnerability/CVE-2024-43819

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-43819/
Summaries are generated and may contain mistakes; the official description above is the record.