# CVE-2024-36844: Use after free in n/a

> Attackers can cause a Denial of Service in libmodbus by sending a crafted message to the unit-test-server, exploiting a use-after-free vulnerability.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 May 2024
- **Updated:** 3 Nov 2025
- **Also known as:** DEBIAN-CVE-2024-36844, GHSA-2625-j643-gg22, JLSEC-2026-1255, UBUNTU-CVE-2024-36844

## What is CVE-2024-36844?

CVE-2024-36844 is a high-severity use after free vulnerability in n/a, published on 31 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libmodbus v3.1.6 was discovered to contain a use-after-free via the ctx->backend pointer. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted message sent to the unit-test-server.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-36844?

It affects 1 product.


Products: Libmodbus Libmodbus.

## How do I fix CVE-2024-36844?

Upgrade to a fixed version.

## Is CVE-2024-36844 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-36844 exists.

## Other vulnerabilities in n/a

- [CVE-2023-26793](https://insights.sbomify.com/CVE-2023-26793/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-36843](https://insights.sbomify.com/CVE-2024-36843/): Memory corruption in n/a (high 7.5)
- [CVE-2024-34244](https://insights.sbomify.com/CVE-2024-34244/): Memory corruption in n/a (high 7.5)
- [CVE-2024-10918](https://insights.sbomify.com/CVE-2024-10918/): Stack-based Buffer Overflow in libmodbus library (medium 4.8)
- [CVE-2024-36845](https://insights.sbomify.com/CVE-2024-36845/): Denial of service in n/a (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-36844 and fix it if it is affected.

What it is: CVE-2024-36844 is a high-severity use after free vulnerability in n/a, published on 31 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-36844 exists.

Affected product: n/a. 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-2024-36844/ (Markdown: https://insights.sbomify.com/CVE-2024-36844/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-36844
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-36844
- OSV: https://osv.dev/vulnerability/CVE-2024-36844

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-36844/
Summaries are generated and may contain mistakes; the official description above is the record.