# CVE-2024-3935: Eclipse Mosquito: Double free vulnerability

> A remote attacker can crash the MQTT broker by sending a crafted packet when bridge topic remapping is enabled.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Oct 2024
- **Updated:** 3 Nov 2025
- **Also known as:** DEBIAN-CVE-2024-3935, GHSA-r5mw-c5jc-r788, ROOT-OS-ALPINE-318-CVE-2024-3935, ROOT-OS-ALPINE-319-CVE-2024-3935, ROOT-OS-ALPINE-320-CVE-2024-3935, UBUNTU-CVE-2024-3935, openSUSE-SU-2025:15074-1

## What is CVE-2024-3935?

CVE-2024-3935 is a medium-severity use after free vulnerability in Eclipse Foundation mosquitto, published on 30 Oct 2024. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In Eclipse Mosquito, versions from 2.0.0 through 2.0.18, if a Mosquitto broker is configured to create an outgoing bridge connection, and that bridge connection has an incoming topic configured that makes use of topic remapping, then if the remote connection sends a crafted PUBLISH packet to the broker a double free will occur with a subsequent crash of the broker.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2024-3935?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mosquitto` | openSUSE:Tumbleweed | All versions | 2.0.21-2.1 |

Products: Eclipse Mosquitto.

## How do I fix CVE-2024-3935?

Upgrade to a fixed version.

## Is CVE-2024-3935 being exploited?

There is no known exploitation of CVE-2024-3935 in the wild and no public exploit code.

## Other vulnerabilities in Eclipse Foundation mosquitto

- [CVE-2018-12550](https://insights.sbomify.com/CVE-2018-12550/): Auth bypass in Eclipse Mosquitto (high 8.1)
- [CVE-2018-12551](https://insights.sbomify.com/CVE-2018-12551/): Auth bypass in Eclipse Mosquitto (high 8.1)
- [CVE-2023-5632](https://insights.sbomify.com/CVE-2023-5632/): Unconditionally adding an event to the epoll causes excessive CPU consumption (high 7.5)
- [CVE-2023-28366](https://insights.sbomify.com/CVE-2023-28366/): Denial of service in n/a (high 7.5)
- [CVE-2021-41039](https://insights.sbomify.com/CVE-2021-41039/): Denial of service in Eclipse Mosquitto (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-3935 and fix it if it is affected.

What it is: CVE-2024-3935 is a medium-severity use after free vulnerability in Eclipse Foundation mosquitto, published on 30 Oct 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-3935 in the wild and no public exploit code.

Affected product: Eclipse Foundation mosquitto. 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-2024-3935/ (Markdown: https://insights.sbomify.com/CVE-2024-3935/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-3935
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-3935
- OSV: https://osv.dev/vulnerability/CVE-2024-3935

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-3935/
Summaries are generated and may contain mistakes; the official description above is the record.